Update 2011: I hadn't been to Herbivore in a few years but I find that not much has changed. The food here is competent, at best, and in some cases it really falls flat.
I liked my seitan breakfast sausage (~$6) with pastry (which was kind of like a breakfast sandwich), but the crispy tacos (~$7) fell flat because of stale shells. That's a serious quality control issue, Herbivore!
Similarly, the falafel wrap was way too dry and the falafel pieces themselves overly crumbly.
I wouldn't go out of my way for Herbivore but I'm glad it's around. That said, they have lots of room for improvement.
Original review, 2008: I had already tried the other Herbivore on Valencia, so I came to this one to see if there were any differences. The Divisadero location is nicer and trendier, and the interior space is slightly more upscale as well. However, the service wasn't nearly as good as at Valencia. At first our waitress was attentive, but gradually seemed to lose interest, prolonging our presence for longer than we thought.
Also, the food didn't seem as good as at the Valencia location. My zataar appetizer was overly-seasoned and the bread was too chewy and hard. My gnocchi was sparse (there were maybe a dozen pieces of gnocchi, floating in a sea of tomato sauce) and not filling and definitely overpriced at $13. However, my partner's "chicken" sandwich was good, just as good as at the Valencia location. Judging from these two visits, I would have to recommend the Valencia location over this one.