Basically, Titans have a ground pound style super for their "Striker" subclass, it's Arc which is good, other subclass, "Defender" has a bubble shield thingy, can give you and your friends an extra shield or a nice increase to gun damage you deal, or all damage i guess, Warlocks have Sunsinger so they can revive themselves and be very strong while in Radiance, Voidwalker which throws a giant glob of void and shtuff. Hunters can take out there blade in Bladedancer and can go invisible while in it (also other ways) and Gunslinger can pull out a flaming pistol which is very powerful, I personally am a Titan and that's my fav character, so i don't know much about the others but the Titan has some very good exotics to it, but then again so do Warlocks/Hunters, all depends on your playstyle, hoped this helped sorry I'm not that great at explaining things so yea lol.