Considering this was the first stereo I've ever installed on my own, it wasn't too bad. I did it in the dead of winter though, so that was dumb...and made it more difficult than it should (read: cold fingers).
It was about a 5/10 as far as difficulty. Pulling the dash is pretty simple. It was connecting the wiring harnesses that was confusing. While crutchfield's diagram is correct, it seems confusing because some of the mating wires have different colors on the insulation on the wire, but sure enough they were correct. Bottom line, trust Crutchfield's wiring diagram...they know what they're talking about.
Here's a link to a thread on installing the Metra steering wheel control. You need this to keep the functionality.