A new CDP after my Rega Apollo or a new DAC?

I've owned both the Apollo and the Cambridge 840, but none of the others you mention. I like the Apollo -- very musical for a CD player. But I kept (and still own) the 840. More solidity, more detail (but not etched or bright), more of a "you are there" sense to the midrange, and no annoying "initialization" of a CD.

A used Naim CD5X can be had in that price range.
Much better than the Rega Apollo, IMO.

I picked up a Raysonic 128 recently and couldn't be more pleased. My last digital rig was an APL Hi-Fi full blown Denon 3910 w/AKM DACs. Excellent sound but I dumped it two years ago and have been listening to vinyl exclusively ever since(Galibier,Tri-Planar,XV-1s).

Having a large collection of CDs and finding vinyl a pain to play when we had company, I figured I'd break down and buy a cheap one box player. Fortunately, I heard a friend's 128 before I'd pulled the trigger on anything and bought one for myself.

I've put approx. 300 hours on it since it arrived four weeks ago and find myself listening to my old CD's once again and actually enjoying them, quite a surprise!

Lest you think the 128 is just a "mid-fi" player and not capable of excellent sound with high resolution, mine feeds an Atma-Sphere MP-1 Mk III with all upgrades and MA-1 Mk III monos, again with all upgrades. Believe me when I tell you, if a source is not up to the task, those two components will let you know in a hurry.

One last thing, it sounds fine with the stock tubes but I replaced them with NOS Telefunkens after about 200 hours with great results. I intend to pick up some of those cheapie Philips to try as well. No, it's not an EMM Labs or some other mega buck player but it's close enough that I can easily live with it for the foreseeable future.

You don't care for the Benchmark?
I have a Rega Planet and I'm considering purchasing a Benchmark DAC-1 Pre. My system is already on the thin, dry, wiry side. I thought the Benchmark would help. Perhaps not?
Some reviews rave about its ability to reduce the digital nasties, others say it's a bit sterile. Are you considering selling yours? How does it sound compared to the Rega Apollo?
Sorry I'm not helping to answer your question, but your system is way ahead of mine already.

Obviously its system dependent but in my system, the Benchmark DAC1 PRE is not harsh, cold, lean or analytical. I like it better than the Rega Saturn (I own 2 Saturns). I use the Saturn as my transport for the DAC1 PRe. IMO, the DAC1 PRE is truthful and natural sounding whereas the Saturn and Apollo add some coloration. BTW, I used to own the Apollo before I upgraded to the Saturn. I couldn't be happier with the Benchmark. It's also a very good headphone amp. It drives my Ultrasone Edition 9 headphone very well. For reference, my system consists of the Harbeth Super HL-5, McIntosh MC275 power amp, Convergent Audio Technology SL1 Ultimate preamp, REL Strata III subwoofer and Running Springs Jaco power conditioner.