Krell KPS25SC- How good is this piece really?

Aside from enduring the withering criticisms on Audiogon and similar sites I think you would hear that this piece is very musical and easy to use. I don't think most people have heard this unit. I use mine with a FPB 400cx with the CAST cables and think that it sounds wonderful. I have a room that is great for listening (very well damped and no reflections) and think that the room is more important than most people will admit. I don't know that I would've bought this piece without the great price I got thru Audiogon. But I would unhesitatingly recommend it. In addition to sounding great it also eliminates an additional piece of gear in your system; better for sound, space, and cheaper (no IC cables) because CAST cables are much cheaper than top of the line IC cables (although I have heard that Siltech is going to make CAST cables).

I have a Krell KPS20iL and a 700cx. I've been considering changing to the 25sc for all the advantages that it seems to offer - but I have no opportunity to compare it with my existing unit. Does anyone have any opinions on how the two compare?

It is awesome and EASY to use. Used in conjunction with a Krell amp utilizing the CAST system it sounds better than with Valhalla XLR's! Siltech makes CAST cables that best Krell's.