Has lots of potential to be a great game but sadly won't live up to it's potential due to incompetent developers.
This game had been in closed beta for almost a year and had a major rework due to the negative backlash and criticisms over their shoddy mobile-games style "pay-to-not-wait-X-hours" business model. Amazingly, it took them almost a year before they realized their business model ain't working for a PC game - despite the constant complaints and whines of the players.
Game got rework and released open beta on Febuary, 2014. It was buggy and unbalanced, but that was expected as the game was in beta. What's not to be expected though, is for devs to start shoving DLC, unnecessary content, and locking characters behind a paywall - when the game is supposed to be testing for bugs and balance. Isn't the whole point of a beta to flesh-out the kinks of the game? Not "try to milk as much money from your players before the game even gets a full release"
My major complaint about this game though - is the terrible pace of balance fixes. Patches usually come in a bi-monthly basis. People have listed problems with the game's balance ever since the start of the open beta - problems that made the game repetitive, stale, and boring. The devs even acknowledged these problems themselves even as early as March - yet they barely touched the balance when it comes to patches; it's usually 1 minor balance change followed by more DLC, content disguised to entice you to spend money on blings (*cough* crafting patch *cough*), or advertisements.
The slow pace of balance changes results in a sorta flavor-of-the-month setups where people will just resort to the most imbalanced setups that's currently available. This is what makes the game a repetitive and boring choir, as 90% of the time, you'll find people are just using the same setups with little variations in their defences. This trend had been going on for over 6 months from the time of this review's posting - and looking at how the devs are more content to shove DLC on your face than listening to player's feedback in a friggin' beta - then this game ain't going anywhere.
TLDR: Game is rotting in beta with devs trying to milk as much money from players as they can instead of fixing bugs and balance; Also Ubisoft DRM (U-play) sucks.
Update: The game has become Pay-to-Win again - with the introduction of defense crafting. This patch introduced crafting rare monsters by collecting rare materials - these materials are so rare that most players who don't spend money on the cash shop will usually have less than 5 rare monsters in their defenses - whilst people who just outright buy the materials from the cash shop will has 30 or more rare monsters in their defenses. Absolutely disgusting - do not touch this game unless you enjoy paying money for unfair advantages.