This place used to be a great resource for vegans in Mexico City - they used to stock the vegan Tofutti cheese slices and lots of frozen vegan products imported from the US. They still stock the Tofutti sour supreme, plain cream cheese and ice cream but they no longer appear to have the cheeses. I've asked them about getting the cheese slices back in but they don't seem very interested.
Still it's a decent place to pick up some essentials. Remember that they close early on Fridays and remain closed until Sunday.