The Optoma HD72 I have is great and the reviews for the HD70 are pretty good, too, especially if you want to save some money. I can't say enough about how much you need to pay attention to the installation restrictions, though. The lack of lens shift and the very small zoom capability is a really big factor with these, both of which mean the image goes to a very defined space (and size) on the wall, with little flexibility. If you have the luxury of mounting it anywhere on the ceiling and aren't too particular about screen location (being able to paint your own on a wall helps), then you can mitigate these limitations somewhat. But be sure to check out Optoma's web site for the measurements, geometry, etc., to make sure they will work for you. Also, Optoma was including a free replacement bulb for a while, but they probably have discontinued that by now.
Cheers,
Kevin
p.s. don't forget that they also have only digital keystone correction, which can negatively impact performance if you have to use it.