You forgot one category....
The out-of-reach-to-the-average-consumer industrial solid-state hard drives.
If I understand it correctly (as I told you earlier), is that the compact flash cards have the limited write issue. There are ways around this using EWF, but I'm certainly not an authority on this.
As I understand it, EWF basically creates a static windows image on the CF card. One drawback to that is the difficulty in changing your windows configuration and setup, I would think. Again, I've no experience in this area.
The other drawback, that I see it, is one of speed. From what I've read, the speed of a CF card setup is about the same as a hard drive, so the performance benefit isn't there. I may be wrong about this.
Lastly, the read/write performance (which is what's going to increase Windoze performance) is present on the uber-expensive solidstate drives from Memtech and Transcend.
Again, all these are my morning ramblings, hypotheses and theories that are not based on any sort of experience.