A lot of 2.1 Roms with HTC Sense have been released for the Hero lately due to the availability of the HTC Droid Eris sources.
Stability and Speed is awesome!
Here is a quick review on VillainRom 3.1 for the HTC ( available at http://forum.xda-developers.com/showthread.php?t=622468 )
- very Stable
- great Performance
- new HTC Sense and Widget features
- Screen Overview (press Home on the Homescreen or Pinch)
- all working 2.1 features (Market, Navigation, Energy Manager)
The official release for the 2.1 Hero Rom is yet to come but regarding the VillainRom you wont have to wait any longer for the stable Android 2.1 with HTC Sense.