First hands-on impressions
I picked up one of the current, and very purple, CI20's a few days ago. As far as performance goes, I agree that it runs like a dog - but that dog is at least part whippet. I was surprised that the xfce desktop is actually quite useable - similar in speed to my regular home desktop machine of maybe four years ago, and not unlike the corporate issue box that whines away on my desk at work. Except that it's silent, cold, and draws a pitifully small amount of power. I did notice that the feel of the desktop improved, unexpectedly, after enabling xfce's compositing option - yes, there's still a little tearing, but let's be realistic with expectations. I got this board as a hobbyist toy, not as a Playstation substitute.
One interesting feature of the CI20 is the availability of a version of Android - currently there's an image of Android 4.4 on the Embedded Linux wiki (http://elinux.org/MIPS_Creator_CI20). That should provide some amusement for rainy Bank Holiday weekend. The limited ability to interface with PI hardware hasn't yet annoyed me, but perhaps it will. Or perhaps I'll take it as challenge.
If there's an underlying issue with the board it's maybe this: it's trying to be both hobbyist chalk and developer cheese. Given Imagination Technologies core business is processor design, it's maybe no surprise if it fits the developer role better, at least until a hobbyist community grows around it.