I've been using a Topaz 24 channel (original version) for a few years now, and it's a perfectly usable board. I had the chance to get a Soundtracs Solo board, but I actually chose the Topaz, which is technically a step down, because it had a cleaner sound. The Solo is a nice board as well, but it was a bit more colored sounding than I was looking for.
Aside from the cosmetics, I don't really know what the difference is (if there is one) between the initial Topaz and the Project version. A price of $600 seems good to me. What other good sounding 24 ch. board can you get for that price? Oh, when I got my board, I changed all the ins and outs to +4. They shipped at -10, but with some soldering, they can be changed to +4.
Yeah, the manuals are a bit pricey for what appears to be a photocopy of a photocopy.
Oh yeah, I bought a Topaz based on many of the comments by Harvey Gerst, but I can't remember where I saw them posted.