CD Player: Vintage or modern ones?

Some capacitors start degrading from the moment they roll off the assembly line. They have a built in lifespan, which might be a decade or two, but eventually they will all fail. So even if a CD player has never been used it could still be at end of life. There are a lot of players from the 90s and 2000s that still sound great but I'd be worried about them no matter how little use they have had. 

A vote for modern CD transports. Using Jay's cdt2-mk3 with Snake River boomslang AES cable to Gustard A26 dac with outstanding results. However it will set you back a few $. Gone the way of Marantz 6005 CD player, Cambridge CXC transport and PS Audio transport, and none of these satisfied my tastes.

New cd player is the way to go. 

I have a spare Cambridge 640C, and a Pioneer Elite stashed away while I'm using my OPPO player. Not sure what I'm going to do when they burn out. Probably get a transport and run it through a DAC.

Given you are asking about "old glory" CD players, I am assuming this means you are open to used?  If so I agree there are not many "old" players I would recommend, and they would generally need upgrades / modifications (e.g., the Sony CDP x777es)  But if you are willing to consider "recent" units, there are many, many good options. I would also NEVER recommend buying a new CD player - such plyers decline in value so quickly you really should go used.

With that said, your price range seems to be about $2500-4k based on the units you referenced.  Just looking on the 'gon (with the limitation that it has to be black, which I will never understand either aesthetically or sonically), you can pick up a Mark Levinson No, 512, which was $15k not all that long ago, for $3k, and it would give you perfectly fine sound.  Or on US audio mart, there is an MBL 1531 for under $3k - a very musical CD player. 

Maybe if you give more specifics on what you are looking for, you price range, sound preferences, etc, you can get more tailored advice.