The game is a unique addition to the MC franchise. Gameplay-wise, and scale-wise, I'd say it relates mostly to the great boardgame, Siege of the Citadel. Which is good news, since it was the best MC product, better than Warzone IMHO. You get to play four classic MC factions (Capitol, Bauhaus, the Brotherhood and Algeroth), and each faction has a unique gameplay which reflects its identity very well (Capitol is all mobility and ranged attacks, Bauhaus is defensive and mid-range, Algeroth get close combat powerhouses, with a lof ot hit points, and the Brotherhood is the tricky faction).
The game is a skirmish game, which sets it him apart from the WH40K-like AT-43. It plays fast, and also has very simple and elegant gameplay mechanics.
But the most unique aspect of the game, is the way you build your army. Not only do you have to buy your troopers, you also have to buy order tokens (necessary to activate your units) and Command cards (which are situational boni -like bonus attack dice for an attack- used to create deadly combos). There are only three price : bronze, silver and gold. And you get an equal amount of each for creating your force (the starter allows you to play a 3/3/3 game, but the game becomes much better from 5/5/5 on). Bronze troopers are weaker than silver troopers, which are weaker than Gold troopers. The same thing can be said for Command cards (bronze command cards being the weakest). Bronze order tokens grant the activated trooper one action, a silver token gives you two actions, and gold token gives you three. Order tokens can also be used to "buyback" some of the command cards, allowing you to use them more than once in the game.
This gives a lot of possibilities to build a lot of different types of forces : you could field a swarm of low quality troopers supported with top notch command cards and good order tokens, or field only a limited number of gold unist with a lod of command cards and order tokens for buybacks, or simply play a balanced force... All will play very differently, so there's a lot of thought implied in the army building (and the game also allows a lot of combos).
The more you play the game, the better your "feel" for the value of Command cards, troopers and order tokens will get, and you'll experience more and more interesting builds. So the "metagame" and surprise element (since command cards are hidden at the start of the game) are very important, like it would be in a CCG/LCG.
Still, despite this overall "gameishness", the factions specific gameplays and the MC universe gives it a lot of character.
Hope this quick (and not-so-objective) review will help you make your decision !