The "weakness" of the Sonus Ultra-Fine makes it great for cleaning up contamination that's only on your LSP. I use that stuff at every wash and unless the LSP is absolutely on it's last legs the Ultra Fine doesn't do any appreciable stripping. This makes it a perfect clay for almost everything *I* do. But yeah, it's too mild for real contamination-contamination that's embedded in the paint itself.
I think you'll like the Sonus vs. the Griot's, but then it's not like everybody's gonna agree about everything

The Ultra Fine is a bit milder than the Griot's.
Rag- I somehow doubt the Griot's will work all that well for you, given what *you* are claying off. It doesn't clean nearly as well as the Sonus gray (and I'm referring to the earlier, milder version that didn't mar paint).
SVR- I'm surprised you dislike the Glyde so much, but then it doesn't seem to affect my clay the way it does yours and I wear gloves so I didn't notice it on my hands. You *do* have to really clean/rinse it off though, that's for sure. Stuff like UGE is a bit *too* slick for my liking as a clay lube, same thing I thought about using Griot's SpeedShine with their clay.