I just ordered both a mech kb and a tablet recently. Tablet got here first. I'm still waiting for the keyboard. I would suggest a tablet first since it really does require the most training to get use to and is a totally different play style all together. Trust me, COMPLETELY DIFFERENT.
As for which tablet, I did indeed get the CTL-490 (Intuos Draw). The no lag free driver issue is a small problem, mostly only if you hover though. Most of the lag seems to cancel out if you drag. I use the FixMyPen program just now because I haven't in the past and it seem to help some. Though I times I still feel as if I notice the "drunken cursor" I heard about in another forum topic, though this is only on really fast or long jump maps.
If you're only getting the tablet for osu!, spare yourself the trouble and get one that the community already knows works 100%. I only got stubborn and got this because it comes with some cheap graphic art software as a bundle. (That I would love to actually get interested in at some time maybe....)
And for your keyboard later, mechs won't make you faster necessarily, they're just less stressful on your fingers which can allow you room to grow in your speed and stamina. I would advise "strength training" on that plain 'ol rubber dome you got there until you're REALLY good. Then when you get the mech, it'll be easy as pie.
