First of all the hunting styles : this is most likely the biggest change (along with the arts) from the other games of the main series. They're all very cool and gives every weapon a breath of fresh air, having each their strengths and weaknesses. However I feel that it is not the complete truth. As a matter of fact, my brother and I ended up playing almost exclusively with Adept Style as most weapons apart from a few benefit greatly from it (off the top of my head the only weapons who don't benefit as much) are Insect Glaive and maybe Switch Axe, more on that later), despite losing one or two basic moves and having only one equippable art. This is because under normal hunting conditions, Adept Style acts as a free HG Earplugs and gives you an incredibly lenient timing window to evade attacks (think MH4U's Evasion+3 but even more lenient, almost as long as the full dodge roll animation) while minimizing your DPS downtime through strong counterattacks despite the lenghty Perfect Evade animation (Perfect Block animations are very short in comparison, but the timing window is much tighter to trigger one). What this means is that, considering you have prior Monster Hunter experience, you can breeze through most of the game using Adept Style even when first-timing new monsters and effectively turning it into a not-so-Adept Style.

As mentionned earlier however, there are times where we didn't feel like Adept was a good deal. It ranges from Insect Glaive loss of its crucial Kinsect Recall command (at least not before performing a Perfect Evade) which means you cannot get your buffs as easily as before, to Switch Axe which, while not really suffering from any major loss of basic moves, just benefit a lot more from using Guild or Striker style, allowing for 100% damage buff uptime through a combination of Arts.
There are also monsters who punish you for performing Perfect Moves, such as Rajang and some Deviant monsters, basically any monsters possessing multi-hits moves with long reach which requires you to evade quickly and repeatedly (i.e. Rajang's spinning air slam attack).

The other styles are also viable despite their downsides compared to the Adept Style depending on the weapon used since they come with their own many pros, but some styles are simply worse than some others. I will be taking the Bow and the GS as examples, two weapons that I am at least okay with, to write a short analysis for. The Bow's Adept style removes its backhop in favor of the normal dodge roll and the ability to perform perfect evade, along with its Arc Shot which funnily is quite a huge buff because it is replaced by the mighty Power Shot (MH4U's Seregios Bow special shot). However Guild Style is also viable if you don't mind not being able to Power Shot anytime you want. It gives you the newly added mechanic of the Backroll Charged Shot and enables 2 Arts to be equipped at the same time which allows for more flexibility in your hunts. Striker Style has relatively limited use, being a worse Guild Style despite having 3 equippable Arts (apart from the two evade Arts, really only the Bow-specific Haste Rain is a relevant Art) at the same time, as it loses the Power Shot. Aerial Style is complete rubbish however, as Boost Jump attacks deal peanut levels of damage and you should not be at point blank range from the monster anyway, not to mention the loss of Power Shot. Being able to mount a monster does not make up for what it loses, especially considering the mounting nerf in MHGen.

GS is one of the few weapons to have all of its 4 styles situationally useful. Guild Style is a beast as it always had been in previous games, with the added benefit of having 2 Arts. Adept Style is a solid choice for monsters possessing lenghty beam attacks or long recovery animations (Agnaktor lava-beam, Duramboros jump slam, etc...) giving you plenty of time to freely hit their weak spots. It loses its forward strong charge, but it is hardly used even in Guild-style due to the high opportunity cost and long recovery animation. Striker style is also strong, having access to 3 Arts and minimal move losses since it still has the key normal charge attack. Not to mention a buff on its super-strong charge attack Art by reducing its charge time (not the art gauge, but the actual charge animation, I am not sure whether all of the other weapons have some kind of buff on their Arts with Striker style). Aerial Style is the most situational one : it loses the normal level 3 charge for a level 2 charge when grounded, but using a Boost Jump allows for a really fast level 3 charge and can be used to hit otherwise difficult to reach weak spots (Duramboros' back). It is however not easy to be accurate with Aerial level 3 charges even when a monster is downed.

Now I am making it sound like Aerial Style is the worst/most situational style to use but it really depends on the weapon you use and the monster you are facing. I've seen plenty of people doing just fine to pretty good with stuff like Aerial SA, DB, and IG (that jumping distance doe) and it is arguably the most skill-intensive style since it has basically two, although short, iframes windows (1st on the end of the frontflip animation, when the hunter is ready to jump onto an object, and the 2nd same as your regular dodgeroll) and you can use it for the same purposes as Adept-style (counterattacks) minus its longass animation.

Capcom came up with a lot of neat ideas with these styles but they unfortunately not very well balanced between each others for your normal hunting runs. Things might be different in a speedrun setting (MH4U's Hame runs anyone?) so we might see some styles other than Adept shine but otherwise I feel that Adept style is really often the style to go in order to hunt efficiently and it's a shame, especially considering its ease of use (granted, Adept blocking weapons is definitely harder to use due to the tighter window, but usually have more rewarding counterattacks moves).

That pretty much covers what I wanted to say about the styles. Next up is the degree of customization of MHGen in comparison to MH4U. I really do have mixed feelings here because while choosing a Style and Arts to use play a major part in the player's experience, equipment crafting was made much more straightforward. I don't mean the changes they've made when you want to upgrade your weapon or armor, but rather the freedom of armor mixing pretty much gone from the game. While MH4U allowed for an insane amount of possibilities in terms of making custom armor sets and getting the skills you wanted at all stages of the game (and I am not talking about the holy trinity of Honed Blade / Challenger +2 / whatever skill was core for your weapon), MHGen is being very shy regarding the amount of free slots available on any piece of gear as far as non-Elder Dragons armor sets go. I went from low rank Ludroth set, to low rank Rathalos set, to high rank Ceanataur set, to currently the high rank S.Magala set, and the amount of free slots ranged from 2 to 3, to a whopping 7 slots for the S.Magala set. Furthermore, unlike in MH4U, I didn't see any piece of armor granting some points towards a skill that would not be activated with the entire set (i.e. Iirc some pieces of the high rank Gore set gave points towards Sharpness +1 without activating it). While I have not yet unlocked and beaten the end game bosses (basically high rank Elders), I doubt there is enough material to come up with good armor mixes, assuming they all get at least as many slots as the S.Magala set. And let's not talk about how talismans took a huge nerfbat hit in comparison to 4U.

Now there are also the Deviants armor sets which are mighty powerful late in the game when their unique skills unlock, and while none of them have any free slots (I don't think they have any?) they might be key to armor mixing considering you can get talismans with those unique skill points. I have not yet digged too deep in that area but it is worth knowing more about. Anyhow I think it's a shame that Capcom is apparently forcing full sets upon us instead of being open to armor mixing like they were before. Then again they might have hidden the potential of armor mixing rather well but until MHGen's AASS is updated and bug-fixed I have no way of figuring out how things will turn out to be.

Until then I'm just going to beat my way up to unlocking the HR7 limit and see for myself when I get to hunt down the biggest monsters, not to mention I still have many Deviants to take down as well.

Okay I am not sure why I wrote this much in the end, but here's the tl;dr anyway :

- Adept style is arguably the most useful style.
- Styles are far from being perfectly balanced.
- Player customization took a huge hit with the possible lack of armor mixing.

This is only my opinion on the game so far and by no means I am saying that the game is bad, but I am highlighting the seemingly biggest issues I've come across so far. I realize MHX/Gen is basically a really big sandbox/testing grounds for Capcom to see what new features they are going to keep or change for future games, but it does not change the fact that there is a lot of room for improvement. I am still going to grind the shit out of it as an avid MH fan, and the amount of quests available is through the roof, so much that it's sure to keep me playing for at least a couple hundred more hours.