Finally had time to get mine hooked up and load the latest firmware. Mine is hooked to an Optoma H31 PJ, which is 480 native, but will accept up to a 1080i image. Transformers is the only HD movie I own so far and it, looks AMAZING on a 92" screen. I can only imagine what an HD projector would look like, but I'm more than happy.
Popped in a few SD movies and they look just as good as before. I read a lot of reviews and people complained about the load/shut down times, but mine seems very fast. Maybe they fixed it with the latest firmware upgrade.