I know you're asking about the 13" but I have the 17" Wrapsol and it's excellent. Picked it up at Fry's electronics. Its fit is very precise which presents a trade-off: Installation is very cumbersome (very little room for error) as the film covers right up to millimeters on the perimeter but the corollary is a very desirable and discreet fit. My co-worker recommended the Wrapsol and I was sold after I saw the fit/finish on his MBP 15" - he installed it on his own.
You really can only tell that one has the Wrapsol on his/her MBP when you hold it up to the light (assuming it was installed correctly - no air bubbles/pockets). Best $29 and 60 minutes I've spent.
Hope this helps!