Cyanogen releases a fairly stable Android 2.2 ROM for the T-Mobile G1
AndroidandМe is reporting that the upgrade is very stable for a first release, despite a few freezes and restarts it brought upon their G1, but overall ready for everyday use. CyanogenMod 6 has been notably faster than the previous version thanks to the quick JIT compiler in Froyo; moreover, Wi-Fi and the camera now work as they are supposed to. The main glitch is access and installation of various applications from Android Market, which seems to be hit-and-miss with the new ROM.
T-Mobile G1 Specifications | Review