The materials are all top notch and the instructions and pattern make things easy to follow.
I will say that, if I had to go back and do this again for the first time, I would definitely go with a fabric that's easier to work with than the MEMBRANE Silpoly (like the 1.1oz Silpoly PU4000 on the WINTER12 Std kit). The MEMBRANE is so slick and so thin that it's hard to handle. Trying to fold it and/or keep it lined up properly if you're doing something like a double-folded hem is a challenge (albeit a fun one, once you get the hang of it).
Anyway, all of this is due to my own inexperience, having never sewn before. If you're accustomed to using light materials and you're familiar with sewing, you'll have zero issues. If not, practice by making lots of stuff sacks first!!
I have very little sewing experience but I thought if I took my time I could do a somewhat decent job. For anyone thinking the same thing I have this piece of advice; make 1 or 2 stuff sacks with this material before you attempt the tarp. Mine turned out ok but I wish I had practiced first.