I went with classic. Worked just fine for me. Don't think it makes too much of a difference, honestly.
Regarding build, I played a super straightforward pistol user with stealth and throwing, and got through the game without issue.
My build:
STR 6 (for Steadfast Aim)
DEX 8 (put all 6 bonus points here to get it to 14)
AGI 4
CON 4
PER 10
WIL 4
INT 4
Minmax more if you want, I didn't want to lower anything to 3. Perception 10 lets you detect all traps and secrets, gives you huge bonuses to gun skills. Dex 14 gives you 4 shots per rounds with a laser pistol, 2 per round with a plasma pistol, and 3 per round with a .44 if you can make one with a rapid reloader, otherwise 2.
Skills:
Guns (max)
Throwing (max) (don't do this, no point getting more once you can huck a grenade a decent distance with 90% accuracy)
Dodge (max)
Evasion (max)
Stealth (max)
Hacking (max) (don't do this either, no need for more than 115 modified)
Lockpicking (max) (again, don't get more than 115 modified)
Persuasion (max) (don't think you need more than about 100 of this)
I made mistakes. Put spare points in traps and/or crafting skills instead. Chemistry/Mechanics/Electronics - useful blueprints are flashbangs, incendiary grenade, taser, energy pistol, pistol, SMG, energy shield emitter. Dunno if you'll have enough points for all of these blueprints to be useful, but you should at least be able to make flashbangs and incendiary grenades for crowd control. Note I took absolutely no crafting skills and still got through the game okay, but they'd have made it easier.
Feats in order of acquisition:
Aimed Shot, Gunslinger, Recklessness, Steadfast Aim, Kneecap Shot, Opportunist, Sharpshooter, Grenadier, Critical Power, Rapid Fire, Nimble, Point Shot, Three-Pointer, Execute
Execute sucked for me, would've been much better if I could've crafted flashbangs/taser/electroshock pistol. Rest seemed like solid picks.
Equipment wise, I carried lots of grenades (flashbangs and incendiary grenades for incapacitation and fear effects, EMP grenades for shielded enemies, frag grenades for killing dudes), weaponwise I used a plasma pistol and .44 hammerer for punching through things, laser pistol and 8.6mm steel cat for shooting lots of times per round. For armour I used a tactical vest with a black overcoat for most of the game, until I got a certain item from the end of the Protectorate questline. Also ninja tabi boots and smart night vision goggles, and the best high frequency shield emitter I could find.
General advice, get stealth no matter your build. Don't know how I would've beaten the game without it. Trade in your 5mm for a 7.62mm as soon as you find one, then kill the thugs who try to shake you down at Junkyard, one of them has a .44. Check every trader for equipment upgrades, stuff has quality level in this game. Adrenaline shots are the only thing in the game capable of boosting your AP above 50 and are very powerful. Bear traps can be used with no skill and work well in tricky fights in the early game, carry a few.
That's about all I can think of. Let us know if you want to know anything else.