I bought it. It was fun, but not amazingly compelling. The build aspect is a mess, with crap dropped all over the shop. You can gave a chance to build something useful further up in the map and find yourself out of buildings because 5 people decided to spawn bike shops in the base. If you clean up unwanted buildings to allow more useful structures, someone else puts down new buildings and ruins your plan. The end result IMO is a fairly chaotic, standard space shooter. These grandious concepts (Starhawk, MAG, etc.) only work with proper teamwork, which you don't get ordinarily. I had fun building a tank and messing up the enemy, and I can fly the hawks okay a bit. Coop was great when first playing because there was a way to cheat by getting the last enemy caught in the scenery and then farming Rift Energy to build whatever constructs you want, turning it into a base building game. But that was patched and now you only have limited Rift Energy per turn which isn't enough to build anything other than a few buildings which are instantly trashed at higher difficulty levels.
It's an okay game, but it has failed to live up to the potential of the beta IMO. I haven't had such balanced, interesting games as I had then. It's also nigh impossible to play until you've learnt the maps, which requires some considerable hours of play (learn where the mines are, etc.) while up against vets that won't give you a moment's peace, like all these games. Sure, you can learn the maps if you just want to fly around an empty map exploring, but there's no fun in that.