I love Sidux. Really. A lot. It's nice. So far I have only had two problems, both of which were problems I've had previously and don't have nice solutions. They both seem to stem form Kernel issues in 2.6.27+ kernels. It just seems that being where I'm at in the Kernel dev schedule, my stuff isn't fully supported. Namely, NVIDIA drivers and GSPCA USB camera drivers.
No big deal, I'm not all that concerned about snazzy graphics and USB Cameras.
Beyond that, Sidux is fast. It's got KDE on it, but it doesn't bog down at all. My previous experiences with KDE have been Ubuntu based, and they really like to bloat it down with extra apps and such. Here, it's a really nice usable desktop environment.
It's also madly configurable. I can get Sidux to do just about anything that I want it to without it telling me that I have to remove this or that package, and that it's not recommended or some such.
Finally, I'll never have to upgrade again! Yay! Just running regular upgrades will keep me up to date with everything that I need to do!
Did I mention it was fast? Blazingly fast?