These are good stuff. We have tried several different methods for creating interesting multi level terrain and these models rank up there. The design is great with plenty of spots to place minis as they move up, down and across the hills. A few of these spots are at slightly too much of a slant and getting a mini to stay exactly where you want in these specific spots can be tricky. The textures provided are nice. However, after seeing some other products I would have like a few more customize options.
I am pretty much a newbie at paper modeling and I really didn't have any issues with these and would personally consider them "medium" difficulty. They are definitely more involved than a couple walls and a pitched roof and during the later stages of assembly it can take some Dexterity checks to get into the tigher spots to hold pieces while the glue sets but the DC isn't too crazy. (aside - I would NOT attempt these models with normal PVC unless you are into self toture, you really need a tacky glue that is going to set pretty quickly, I have done some simpler buildings with 'normal' glue but cannot imagine how you would do that with these)
All-in-all a solid product that is worth the money and time to build. I would definitely recommend but only wish there were a few more options to add a little more variety.