Ok, gave it a spin, and I have mixed feelings about it.
First the good - unlike the competition, it comes with some great widgets out-of-the-box, and the whole initial setup process is very professional and user-friendly. I think it's safe to say that it's the most polished desktop widget app available.
The first big red flag - it starts up new processes for each new widget that you create, and each process takes up a LOT of RAM. Now this isn't a huge problem for those of us with >512MB of RAM, but it's a little discomforting, considering that every other widget app uses far fewer resources to achieve pretty much the same effect (I compared the FTP Drop widget in AveDesk - it's pixel perfect, but uses less memory).
Another obvious issue is the cost - $25 as compared to $0 for apps like AveDesk, Kapsules, Samurize, DesktopX etc. But Konfabulator does have a larger library of widgets to choose from than most of the others...at least as of now.
Finally, hackability - I think Samurize can be considered the most hackable of them all. You can go in and change things around to suit your purpose. AveDesk would be second in the list. Kapsules and Konfab are almost on par when it comes to hackability - they're essentially not meant for it, so both of them offer you very little opportunity to customize the widgets, and make them any different from what they already are. That also makes both of them the most user-friendly - they "just work."
Hope that was objective enough and helped some of you.