Another addition is this build is preliminary support for persistent cartridge RAM. Some games, such as Phantasy Star (pictured above) let you save your progress in the game onto battery-backed RAM built into the cartridge. If you come back to the game later you should now be able to continue your progress without needing to manually save the entire emulator state.
I've had reports of rather bizarre crashes bringing one poor user's machine to its knees. I'm at a loss to establish why; I've tried the emulator on four machines (two Vista, two XP) and although one of the machines displays a white screen instead of the emulator output (no pixel shader 2.0 support on its Radeon 9000) the software trundles along just fine otherwise (I can at least hear the game music!) The one notable difference between my machines and his machine is that he's using a 64-bit version of Windows, and all of the ones I have access to run 32-bit Windows. To see if this is the issue, I've changed the configuration to x86 (I've encountered strange bugs with .NET code using unmanaged 32-bit code on 64-bit Windows) to see if this will remedy issues, but if anyone has any bright ideas I'd be interested to hear them.