Nathan,
I have a SX H-18 and I'm very happy with the results I've been getting from it. I'm using it with a Tak FSQ-106ED and a GSO RC10. I have had a couple of problems with the camera (early versions of the H-18 had a coating on the shutter blades that sheds dust!) but so far SX have been very helpful.
One issue with the KAF8300 is that it doesn't bin very well. The horizontal shift register isn't much deeper than a single sensor element, so if you try to squeeze binned data through it you will see short horizontal blooms on bright objects. If the Sony chip does this properly then that might be a point in its favour.
Have you had a look at the SX group on Yahoo? There has been some discussion of the new chips and cameras there. It's at
http://groups.yahoo.com/group/starlightxpress.
Cheers,
Rick.