A breath of fresh air in the "MMO..." panorama!
The question is: is this mix ok?
Hell yeah!
First, there's less need of grinding to get exp, cause there are many quests to do that will help you raising your level.
Second, the action part of this game is just cool, because the programmers made a very good work and overall it's very funny: you can spend a lot of time battling mobs (and other players since ther is PVP) not getting annoyed.
Third: there are a lot of stuff like weapons, drives, armors, shields, radars... to personalize and empower your Gear.
Fourth: there are parties, guild, and even a Nation War between the two major factions in the game. So, it's quite a deep game.
About the rest: there are 4 basics Gears (A-Assault / B-Bomber / I-Interceptor / M-Medic) to fit better your tastes and your ways of playing.
Of course every Gear has its own array of skills and components.
Overall, the BEST FREE ONLINE GAME I've ever played.