It is different because players have jetpacks that allow them to 'ski' across terrain at monstrous speeds. The gameplay itself is not very fast-paced though, because the maps are so huge in order to compensate for the speed increase. This is not a twitch shooter at all, and skill revolves around timing of shots and predicting an opponents landing path, which is not found in other shooters.
The gamemodes offer variety and help make sure all of the ~9 classes are useful.
Arena mode is a small map where 2 teams go against each other in order to whittle down the limited enemy respawns.
Team Deathmatch is similar, except that the map is much bigger, and the respawn count is greater as well. In order to keep the fighting focused, there is a flag that both teams can fight for possesion of, and team holding the flag gets double points (which are spend in-match for aerial bombardments and other useful props).
Capture the Flag is in my opinion the core gametype, and is my favourite. Both teams fight to capture the enemy flag 5 times. There is a base for both teams, which has a generator. If the generator gets disabled, all base turrets and many of the classes special weapons (forcefield, etc) will be disabled. You can spend points not only on air strikes, but also on tanks and speeder bikes. The problem is that there is no voice chat, and since this gametype needs team cooperation in order to win, it is held back from potentially shining. This is one of the biggest flaws of this game.
Another annoyance is how heavily focused the game is on unlocks. If you do not want to pay money, it is probably best to choose only 2 of the 9 classes to upgrade. This is because XP is acquired quite slowly, and it would take hundreds of hours to even max a few classes. I am at 30 hours and have 50% completion on 2 classes, but that is not actually halfway to completion, because unlock prices scale exponentially.
This is a really good game and I would recommend it to all my friends, but after playing 30 hours I have gotten tired of the gameplay and have reverted to other pay to play shooters.