Totally agree with Paul. Stick with SRF: it is being actively used, evaluated, and de-bugged by the authors and by users alike. I've been running the latest release with Genocide kernel since it was released and have had zero problems...I would even go as far as to say that it's better than the stock ROM. I've had zero FC's and my battery life is excellent.
With a leak you'll certainly get the flavor of GB, but you won't get the full experience until it's officially released. Better yet, wait for GB to be released and then wait until all the new ROM's start coming out..and in the meantime load up SRF or another ROM and start learning your way around the phone and figuring out what you want in a ROM, etc.
late,
Coz