Don't be fooled. I will start with the most important and that is the poor servers.
Although in major countries there are playable servers available, for any other country, even sometimes to players in major countries, you get placed on a far-away, entirely irrelevant and weak server. Game after game after game is unplayable because an australian player hosts a game and it picks the korean server. Germany or South African player and you get plonked onto an unplayable Tunisian server. Don't even bother, if you are lucky to play online games where broken matchmaking (which gets worse each "patch") doesn't kill your game, you will get bored as heck- read on why.
So you joined the game, you just passed level 10 and you can't join a single game- what gives? Well, too bad, you missed the first wave of beta players boat and they don't give a heck about you. The active players play exclusively with each other and farm with each other. New players get to play with new players forever, but eventually they all quit as there is no incentive to play, which brings me to the following:
Levelling up in this game is utterly pointless. You earn a few locked diamonds (you have to spend real money to unlock them) at level intervals but levelling up is so boring, tedious, mediocre and repetetive that you either realise what a waste of time playing this game is, or you slave away, losing your soul game by slaving game, until you reach level 25 and hate yourself for trying, because active players buy their way to level 100+ with real money bought boosts and exclusive groupies.
This game is fun until level 5-10ish. After that, it becomes stupendously mediocre and repetetive.
The only new and temporarily interesting content in the game is bought with real money through the in game currency (diamonds). You can earn some of this currency in-game, but it will be locked and unusable until you spend real money to unlock it. These items bought with diamonds are purely cosmetic- so after unlocking several cosmetic items, you realize what a total waste that was as there is no benefit to having more than 6 cosmetic items as you can only equip 2 sets of 3 items at a time.
New content added to the game that can be unlocked using in game money (kudos) are all the same. Roughly once a month 1 to 3 new items are added but these items are identical to existing items (that you likely already own) and only differ in icon-appearance. New items are therefore always redundant, pointless and useless.
I feel I have warned you enough by now, and if you ignore my warning and play this game and realise you should've listened, servers you right. Enjoy hating yourself. I'm getting sick of writing a review about this game, with its uninspiring, lame and unhelpful dev's who only cater for the select few level 100+ players that virtually fund this game by themselves.