I have a 508.24 and a 506.18. At least, I think it's still a 506.18. A few years ago, it was skipping pretty bad, so my friendly dealer sent it back to meridian for me, where it was fixed, loaded with the latest software, and given a new dac. This was so long after the production run, who knows? No charge for any of this. Sounds great. It's in a different room from the 508, which is clearly better, but I don't sit there thinking, gee this cd would sound better in the other room - I just enjoy.
The Classe is also very good. I'm sure some people might prefer it over the meridians. If you like the sound of the 506, what do you think is missing? What is the more that you want?
My suggestion is to try to listen to what you're interested in, and, maybe, even try the latest inexpensive 24 bit cdp from, say, NAD. One thing I wouldnt do right now is spend a lot of money on a cdp.