Of those two, I would go with the Optoma, hands down. I like DLP, though, so I'm biased.
If you don't see rainbows or get headaches with DLP, I don't think you can beat the picture in that price range. The DLPs tend to have better blacks, more contrast, look more filmlike to me and you don't have to clean out dust blobs.
Be aware, however, of the lens offset on the Optoma! Make sure you have room (ceiling height) to mount it without your screen being 6" off the floor!