Well, Garden of Giverny just arrived.

From a newbie perspective, it was easier to install than I expected, though I will say that if you get neurotic about lining things up perfectly, etc., you may want to go with one of the lighter colored skins--preferably one with lots of white. LOL
Seriously, this wasn't too hard to install at all. I put on all the individual buttons first, figuring they'd be a little easier to start with. Then applied the front decal, starting at the bottom with the keyboard. For me, it was easiest to hold that by the lower sides with both hands, with the rest of the decal bent towards me (over my hands). By holding it taut, but not too tight, I could keep the circles for the keys in sight and just move it back and forth until it was centered properly over the whole keyboard. I then used my thumbs to "tack" it down in a few places before trying to apply the whole thing. Smoothed it out lightly around the keyboard with a microfiber cloth wrapped around one finger before moving upward to the sides and top. It worked remarkably well!
As someone else posted, getting the back lined up well is actually harder. Their tip of nearly covering the speaker holes around the edges did a fairly good job of lining up the skin. Again, I held the skin from the bottom sides with the rest of it folded towards me, tacked it down with my thumbs once I had it in position, and then smoothed towards the top.
Looks great, and was easy enough to apply that I just might consider a couple more!