I've racked up about 15 hours so far, have to say this is above my beta expectations, seen a few benchmarks posted around the web suggesting you need top kit to get good frame rates maxed out, but my own experience proved that wrong, it seems pretty fluid and once they sort out the server crash issues I'm sure it will be just about perfected for multiplayer on the main game. So far haven't come across and other bugs or glitches.
It's not all perfect in the co-op mode however, noticed a few silly glitches...
1. Can't shoot through the barriers on bridge once the metal sheeting is blown off, yet enemy can, on mission 1.
2. No option to select ho will be pilot/gunner on mission 2, which is very annoying as my co-op mate can't fly for crap.