sbyrd, I work for KM as a production specialist. I, along with most of KM, will admit the C8000 turned out to be a bit of a bust. The service issues related to the 2nd fuser, the poor front to back registration, colors running hot on the red, long warm up times, etc. We've had (and currently have) several incentives in an attempt just to get the C8000's out of the field, because they weren't profitable to us on the service. Check with your local sales rep. The new line, the C1085 and C1100's have been very solid products. I've sold about a dozen here and every customer is happy with them...many were upgrades from old C8000's and they have now become my best referrals, after being quite unhappy with the C8000. The new units don't have a 2nd fuser, they run full rated speed on all stocks up to 16pt, the registration is very tight, the reliability has been amazing, and the color is better than ever.
To your point about the booklet maker, I'm guessing you have the SD-506? The 200 page unit with the face trim? I'd recommend getting a demo on the upgraded unit, the SD-513. It now offers 3-knife trim, inline creasing, and a square-back option. You can do up to 4 staples, and up to 4 crease positions (ideal for perfect bound covers). You can also use the top and bottom slitters and creasing on flat sheet output, not just booklets. The paper path is much straighter on this new unit as it no longer has to turn a 90 degree angle.
Good luck in your search!