As a player of it I have to say its very addictive, and unlike a lot of these sort of games I didn't have a problem with having to wait to continue playing.
The health regeneration is reasonable and as long as you focus fire on the spirit opposite of the spirit you want to keep damage free you can chew through the trash mobs no problem.
Make use of the bonus stat mechanic on your uncommons and you can undoubtedly keep your Rares and Super Rares damage free until the moment you can bust them out on the boss.
Destiny orbs aren't implemented all that well honestly. More spirit space (10 orbs for 5 spaces) is very nice, but all those other little payments you can make are worthless. Take the 10 orb purchase to make trades instant for example, it only instantly finishes the trade on your end meaning that if you were planning on trading heavily with the other person you either have to wait anyway, or they'll be required to spend 10 orbs too.
Advanced summons that cost destiny orbs aren't a great shortcut either as the rate on pulling Super Rares from them is abysmal, and many of the rares in advanced are simply horrible (seriously some of the worse rares in the game are in advanced for god knows what reason).
