The second map being unlocked for Battlefield 3's open beta is Caspian Border, a massive 64-player conquest map filled with planes, jeeps, and if you get the right server, tons of lag.
The Caspian Border servers (in the PC version, at least) are currently password protected, but the nice folks at DICE are rather free with those passwords (thanks Mrsoftey2!), so this morning I had a chance to hop into a match and bounce around for a few minutes.
As you can see, there was much bouncing.
I attribute the lag in the server I was on to a mass of European and North American beta testers desperately trying to get a taste of the massive map. The servers were all full, all the time, and I suspect the only reason I got in this one was because folks got sick of the rubber-banding and left.
Later I got into a much less laggy version of Caspian, where I stood around the airstrip with seven other guys, waiting for the jet to spawn. Everybody wants to be a jet pilot.