It's pretty damn good, but that said it still only seems like an evolution of Desert Combat, as opposed to the revolution of BF1942 the hype promised.
The Squad system is useful, but pretty unwieldy unless your leader is the sit back and direct type. The commander system is better but prone to misuse (like artillery striking a point you've just defended...DOH!), Also good are the destroyable base features that limit the commander's abilities (just sneak a special ops into their base and C4 the lot!)
The classes are good, but again are a natural progression from Desert Combat. At least the AT soldier can defend against infantry with his MP5 now.
Vehicles were pretty much the same as DC, but stationary SAM turrets really spook the chopper pilots, who thankfully have flare countermeasures.
Lastly the bots are a lot better, seems the AI has had a decent rework. They will obey player orders and report back on size and location of enemy forces...they still tend to focus on the player avatars rather than the bots, but thats a minor niggle.
Can't wait for the general release, Yanks expect it June 22nd, whereas good old Blighty gets it on the 24th.