Just purchased and installed Speck Clear See Thru for MacBook Pro late 2008 Model ( black keys ) and wanted to share my opinion.
The case installs very easily and fits VERY well. It adds a glossy look to the case that looks very nice in my opinion. I had previously tried the black satin see thru model which also fit very well.
I prefer the clear see thru as it takes nothing away from the look of the Macbook and allows the apple logo to shine through very clearly. While the logo is visible through the black, it is not as bright and takes on a purple hue. Not a big deal, but not my preference.
I can see that the clear will show small micro-scratches in the light as they develop. The black, on the other hand will hide scratches better, BUT shows fingerprints much worse. Pick you poison here....but I don't like fingerprints.
Obviously, it adds a little weight, but nothing that I find objectionable. The laptop with the case stills fits in my case logic reversible sleeve.
Anyone who has a new unibody MacBook Pro knows that the screen hinge is a little looser and the lid tends to "flop" some when at held at high angles ( as when laying on back on couch for instance ) The weight does tend to make the lid flop shut more easily.
All ports are readily accessible. My Kensington lock works fine.
Overall, I like it very much. My concern is purely limited to whether dust or dirt under the case would lead to scratches as some have suggested. I believe that regularly removing and cleaning the MacBook and case would prevent this. Incidentally, I had no problem at all removing the case from the MacBook.