Pros

+movement, controls, aiming/firing are all very fluid and fast paced

+beautiful graphics overall. maps and mech designs are gorgeous.

+great sound, special effects, and explosions makes every hit feel really great (and enemy kills feel very rewarding).

+gameplay modes (siege, team deathmatch, missle attack) are fun and intuitive  

+wide variety of mech types, playstyles and weapon/ability customization.

Cons

-class imbalance

-level imbalances (fighting a max lvl enemy mech while you are lvl 0 sucks)

-needs more maps

-cash shop imbalance: currently its takes a bit too long to buy simple low lvl upgrades and even longer to unlock a new mech type

-might be too simple of a game to have longevity?

-matchmaking seriously needs to be fixed (getting forced into an empty server repeatedly sucks)

summary:

gorgeous graphics, extremely fun and fluid feeling but i feel like it either needs more maps or more complexity in order to have longevity. gameplay is relatively simple, it feels like i am playing robot version of call of duty or BF3 except that you can pay in order to rank up and get your weapon unlocks. I'm more used to complex games like starcraft 2 or League of legends.