I agree with your premise, the CD23 is the best value of the bunch. It's a tough call between which sounds better, the 23 or 33. I preferred the 23 by a small margin, due to its smoothness. The 33 is a little more forward, which some of my friends prefer.
I've listened to the 23 headsup against an A5 and preferred the 23. The overrall soundstage was wider and deeper, and there was better bass response.
I agree with the above poster, the Ayre CX-7 outdoes them all. But the main advantage is only if you're running balanced. If you're running single-ended, I'd say it's 5% or so better than the 23. If it's balanced, it's more like 15-20%. I switched from the 23 to the Ayre because I got a balanced amp, but I thoroughly enjoyed my time with the 23.
I've listened to the 23 headsup against an A5 and preferred the 23. The overrall soundstage was wider and deeper, and there was better bass response.
I agree with the above poster, the Ayre CX-7 outdoes them all. But the main advantage is only if you're running balanced. If you're running single-ended, I'd say it's 5% or so better than the 23. If it's balanced, it's more like 15-20%. I switched from the 23 to the Ayre because I got a balanced amp, but I thoroughly enjoyed my time with the 23.