Plain and simple, no stat boost and a limit of 3 powers for you gear. If it adds and element power, then only 2 powers.
Hollows Bounts and Vaizards cant make gear.
Quincy Soul reapers Humans and Mod souls can only have one power each and can only carry two unless the gear is a high skill level such as 4, then only one. You can have a level 3 and level 1, level 2 and level 2 or a level 4.
Bakkudo have to drain stamina and will KILL you if you use them to long.
Humans can have guns. If you want dueling guns, each one has to be about a 2.