CyanogenMod 9 is stable; 10 is underway

The main problem it seems is that the hacks necessary to make an enjoyable ICS experience on QSD8x50 devices don't pass the muster of the Android Compatibility Test Suite, which the Cyanogen devs puts a very high priority on. Also, hardware video recording and playback are still rather broken.

Now in my experience on my original Droid Incredible, ICS does work pretty well, and I haven't come across any explicit compatibility problems, but I suspect that withholding official CM9 support from that class of devices is warranted.