I tried it VERY long ago, it wasn't bad, but the match making system was stupidly awful back then,
it still is. its better, but the que after a certain amount of time, tosses your team with whoever.
They also find it easier to nerf characters as opposed to buffing others. Resulting in many characters becoming unplayable or forgotten.
They have LOTS of problems. Such as the points you get from playing matches. you can unlock heroes with enough points, but you have to save up large amounts. And recently, they have been raising the amounts and lowering the point gain. pretty much as a way to force players with limited patience into actually buying the characters. then theres other stuff- runes. they beef up your abilities. but you can ONLY get them with the in game points. you cant actually buy them. And they are overpriced, So couple that with the nerfed point gain,a nd the insane character point requirements, yeah...
but the game is fun.

Agreed though, the wallpapers are nice. Especially the chinese ones.