I would say that Global agenda is probably the game of the day, I'll sum it up. It's HIGHLY underrated.
The game is extremely fast and exciting, but engaging and interesting at the same time, it blends pvp and pve very well and rewardingly.
There are 4 classes:
You have the recon, a spry fast, high spike damage character that can get away from a bad situation if need be. Probably the hardest class to play WELL.
The assault: Your classic 'tanky' character, They can fill a few roles, machine gunner, rocket launcher, etc. Probably the easiest class to play.
The Medic: The medic has 2 roles, the stereotypical healer role and the role of being a 'poison medic'. Poison medics probably have the highest damage potential in most of the CTF type maps due to the nature of their aoes. Pois medics are extremely powerful and if played right can really dominate a match.
The robo: The classic 'builder' class. They have 2 class specific trees, drone and ummmmm builder. I forget the builder trees name, but you basically build turrets, these include turrets that can basically kill ANYONE in a matter of about 1-2 seconds if they don't have a healer. Turrets have 100% accuracy and a slight pushback... sorta cheap, a well placed turret can really turn the tide of a close match. Their other spec is called 'drone' drones are self-playing robots that help the robo for a short period of time.
There are a few different types of pvp/e: You have 1v1 / 4v4 arena, where you can take a group of people and pvp with them. The 'normal' kind of pvp is 10v10 called mercenary.
Mercenary is split into 5 different types of match (you can select what you want). Control (where you try to control 2+ points on a map to get 800 points first), payload (where you push an objective through 3 checkpoints, or defend against being pushed), scramble (where 2 teams battle over a single point on a map 3 times, similar to breach but breach has set defenders / attackers), breach (similar to scramble, except one team attacks, one team defends. Teams attempt to take objectives, 1 at a time, until all 3 are controlled by their team) And destruction (each team gets a big robot, they have to run it to the other side of the map to kill stuff).
Each class has different weapons that are unlocked as you level. There are guilds called 'agencies' that vie for control of hexes on a map... this is a bit complicated but there is a whole type of combat called ava.
The pve is called 'special ops' and is divided into security levels (med, high, max, and ultramax) and those are just level requirements / difficulty. Pve is usually more of a gearcheck than a skillcheck. There is another type of pve that is open every 90 minutes or so called Double-agent where you have 6 people, 4 attacking, 2 defending. The 4 play a normal pve mission, the 2 play with the computer enemies and try to kill the 4 players pveing.
The last mode that I didn't cover is called "Raid" raid is a 10 man pve-mission where you and 9 others try to defend a 'core' from an onslaught of enemies.
You level / get money and tokens as you play, gear drops, etc...max level is 50
Lastly: the developers are the BEST I've encountered in any MMO. Hands down, period. I think that the game is an 8.5 / 10, but the developers are a 12/10. They really listen to the community. They did away with a p2p model, added a massive open pve / mission based area, etc. They send out surveys to the users asking what they want changed, and how they can go about doing it. Community people / developers are VERY active on the message boards compared to other games I played.
Definitely worth checking out. The only thing the game lacks is a big playerbase, and that's not to say that it's small, it's big enough to do things with.