FWIW & IMO,
I've had CD5i (on loan from my dealer), CD5X, and now CDX2 (which I own) in my system. I wasn't all that impressed with the cd5i, but it peaked my interest enough to go ahead and order a CD5X from my dealer (with no obligation to buy & w/o ever hearing it). I bought the CD5X (new/discounted) and enjoyed it immensely for a few month's, but it planted the seed to climb higher in the Naim chain. I bought my CDX2 used here on Agon and absolutely love it. And once again, I'm itching for more. Not so much in the form of a CDS3, but more in the way of XPS2. I just don't want to spend the $$$$ right now and really wonder how much of an improvement the outboard p.s. would make. The point is, every time I moved up the Naim chain there were significant improvements, with the move from 5i to 5x being the biggest. And PRaT truly is the Naim of the game. ;-)