Its a great game. Fun with 4 people, and more difficult to match!
Only problem i found is its a little too easy with siren, as they are the best pvp AND pve class hands down.
I reccommend getting it, its fun enough to play by yourself, but with friends its even more fun.
The guns are all very interesting to get, and there is a LOT of possibilities. The game makes it actually fun/difficult, 1 player is a bit harder though.
Best guns: Smg 4 shot.
After you level siren pick one of three specs:
1.(pvp better) slow spec. You can slow anything down with one hit, and it lets you just unload on anyone/anything. PVP wise its almost unbeatable as you can use it with a phase hit or smg spray, so you really have nothing to worry about. Slow+crit is probably the best/easiest spec in the game.
2.Crit, just spray and pray.
3. Element, if you combine the right specs all it takes is for you to set anything besides a fire element on fire and it dies very quickly, you gain fire on last perk i believe.