I have dabbled in all, but played most in Sharpshooter. I have 160/160 points in Sharpshooter, 50 or so in Demo and like 15 in Survivalist. Personally I favor the Sharpshootet because it synergizes really well with my style, but the Grenade launcher is amazing. The crossbow seems like it has potential, but the real winner in survivalist is the healing seeker mine.
I'm leaning towards Demo or Survivalist. Demo looks the most fun to play, but it's hard to deny the strength of Survivalist in PvP. I've never really enjoyed how sniping is done in most games (preposterous preference for headshots and no penetrating rounds), so Sharpshooter is an auto-ignore for me, but that's just me.
Sharpshooter is really incredible in PvP and PvE with some huge quality of life improvements- headshot damage scope, stability, reload speed, and weapon handling buffs among them. To be honest, I like it more for the scope, flashbang (providing grwat CC in a large AOE) and reload speed passive more than anything else. The specialization rifle has felt underwelming in many cases to me compared to the grenade launcher, but it shines against the non-heavy enemies.
