I'm pretty delighted with Fomapan 100; at this point I've shot it in 35mm, 120, 9x12, and 5x7, and I feel like it behaves pretty much the same in all formats (the funky blue 120 base notwithstanding). I have had a few pinholes in the sheet formats, and I once got a roll of 120 that had some sort of bizarre coating defect throughout the roll; there's a sample at
http://www.flickr.com/photos/ntenny/3284015097/.
So I'm torn; on the one hand, this is a film with a distinct tonal "look", a grain structure that I like (it's grainy for an ASA 100 film, but I don't mind that), a small number on the price tag, and a smallish manufacturer whom I'm glad to be supporting, but on the other, I have to admit there seems to be something to the quality concerns that people express.
I have the leisure of using it for fun rather than to make a living; if I were shooting really life-and-death-critical material, I guess I have to admit I'd go with something else. (But in that case I'd probably double up on film and d*g*t*l, too, since each has vulnerabilities of its own...)
At EI 50 it has lower contrast (of course) and a really long, tasty tonal scale. I go back and forth on whether I like it better that way or at box speed.
-NT