3? 3 what?
I assume you mean the characters? It depends on what you want, warrior (melee), rogue (range), mage (magic). As you have played other rpgs, I'm sure you know what their advantages and disadvantages are.
Equipment drops are random. The deeper you are in the game, the better the items become. Each items gots differents mods. With thousands of combination of mods an item can have. It really makes this game stand out from the rest.