Sony X55-ES CD player... thoughts?

I am with you. I find the differences in digital gear is subtle - they are there but these differences tend to be dwarfed by individual recording quality (good CD versus bad CD). The difference between a $300 player and a $10,000 player is much less than the difference between a $300 speaker and a $10000 speaker. Or no room treatments versus a complete $10,000 rennovation with acoustics in mind.

Agreed, however, I have never gone back to back with a Rega (or similar) CD player. I was just shocked that there was virtually no info out there on the internet about this CD player!

I had a Sony TAN80ES amp for a few years too - there was nothing written about it either but it was a solid amplifier that performed well, IMHO. I think some people just assume all Sony gear to be crap but it isn't necessarily always the case. They may not be top of the league tables but they make some good products.

There is indeed not much to find on this player. As a former owner of a X559ES I can vouch for the quality of these older cd players. Also no problem with cd-r's.
The only problem is that it is hard to find replacement parts, so if it fails, it's probably the end. But for your enormous investment (although you could buy a bank these days for that kind of money) it's a great buy.