I've just bought AP and was wondering how well does it manage combat encounters? From what I've read here it seems to be lacking, but I've heard that otherwise it's a very good RPG.
Jick Magger is all wrong.
(1) If you want the most 'powerful' build then pistols' Chain Shot is OP, but this isn't a hard game and you'll mow through everything no matter what build you make. You'll get to try every weapon type in the tutorial so choose what you'd have most fun with. Assault Rifles are the next best after pistols, Shotguns are weak but can be fun in their own 'boom boom' way, SMGs are just bleh.
(2) Stealth is a viable build in that you can 'mostly-ghost' almost every level, I've had playthroughs where I just choke everybody from behind. If you level it up all the way you get some crazy stealth powers. There are some fights where stealth isn't very useful, but again, unless you totally suck at FPS-style games, you won't be stuck wishing you oculd respec or anything.
(3) To me this isn't a FPS and it's also not a difficult game, so personally the way to have fun is to mix it up and use a lot of different things (trap mines, fire grenades to set multiple people on fire, sneak up on one dude then martial arts the guy next to him, etc), and/or to set house rules challenges for yourself. But the first time you play, just take a look at the tutorial, read the options, then just pick what you want to pick.
I won't pretend that it's a well balanced game in any way, but I've had a huge amount of fun modding the inis to make the enemies better (basically make your footsteps, shots, etc. noisier, and there's some other settings), using Rookie to not get a lot of skill points, play on Hard, and then do things like try and not kill anybody in that level, use a limited number of shots, etc. Of course you can do that with any game, but I've found that AP really benefits from this because when you make resources / skills scarce and make the basics a challenge, you get to maximise the cool stuff the combat does have. Nothing like waiting in the shadows watching the guards patrol knowing you've only got one fire grenade left and you want to get them all.