This was the first veg*n place I visited in DF and one I'll go back and back again. The range is really good and it's rather soys meat based but as I am a fan of that and it's an opportunity to eat authentic Mexican food, then that's great.
The service is efficient but if you don't know a lot of Spanish have a few phrases ready just to check especially if you're vegan. The staff are very patient though and will help.
Also, if you're a woman here alone, there are no hassles whatsoever.
The health food shop is bloody brilliant! It's one of the few places here where you can find Tofutti, Daiya, tempeh and something like nutritional yeast.
Cons: pain to find if you're a tourist