Wow so many questions! You shouldn't think too hard about them. People are all different, they all experience the game differently, learn differently, play differently. The context is also different, some people play for fun, others for competition.
Just because you seem to underperform when you compare yourself to your friend does
not mean you are worse than him. I know it's a bit hard to hear the following when asking yourself so many questions, because it sounds silly, but here's a universal piece of advice: play as you want, at your own rhythm. Do not bother about others. The more you play, the more you improve, that's it.
About the tablet, don't try to imagine what it can bring you. If you never held one, you can't imagine. Some people prefer using a tablet, others don't. Some people say tablets are easier because they have experienced it and felt like it really is better, but these reviews are only applicable for them. Again, that's because they play differently, the context is different, etc. Getting a tablet won't necessarily make you a better player. Here's a tip about tablets: if you have the opportunity to get one, buy one. If you like it, great, keep it! If you don't like it, then at least now you know what it feels like. You didn't lose your money for nothing.
Wow, I never wrote so much text in the Introductions forum! Anyway, welcome to the osu! forums! Enjoy your stay. And remember: keep calm and keep playing