I brewed this last year, Partial Mash, and will be brewing it again except that I've converted it to AG for this year.
You're going to get liquid gingerbread either way!
I'm sure you'll get more of a chocolate/caramel flavor since you'll be mashing the specialty grains. I can't compare between the two as I've only done the PM version.
Edit: Don't throw away the spice pack that it comes with. The website does not list the amounts of spice, but the packet does. This way you can use fresher spices for next year if you like it, or, I could give you the measurements if you want.