I used it for polishing a body and the surface area seemed too small to make it worth while as I was really trying hard not to get too close to the edges. You're supposed to go at 90 degrees to the last grade of paper each time so I didn't even give it a go on the sides. Maybe I should have gone in circles, but I actually followed the instructions for a change.
It was probably me as I don't have much patience for such things. Sent the guitar off with a tube of T-cut and a few beers to a mate who owed me a favour in the end. Still, he's not done it, so maybe the micromesh was more efficient afterall :D
I've heard good things about it, but as with a lot of finishing stuff, it's horses for courses. Some people swear by it and some don't, you pays yer money and you makes yer choice.
By the way, that kit in Stew-Mac looks a little pricey. I'm sure I got more sheets as well as a polishing cloth and some liquid poilsh to finish it off for about the same price. Have a look around model shops on the net as model builders use it.