After my first visit there I would have given them probably four cows - yet, after five times having lunch at 100% Natural I find myself struggling whether to give two or three cows.
First of all it should be taken into account that there are very few (sometimes none) restaurants in Mexican cities offering explicitly vegan or even vegetarian dishes; in that respect I was pretty relieved to find 100% Natural and not having to order somewhere pizza without cheese or fries with ketchup.
My first visit then turned out to be really delightful. I had a topnotch mushroom soup and some nachos with a mushroom garnish, both simply great, not to mention the lemonade with chia, which also was superb.
Nobody speaks English, but that's quite common throughout the country, at least there is a menu in English which is already a big deal and can't be taken for granted at all.
The second day is was given some kind of aperitif, really hot chili in a small pot and two sauces. At first I thought there was some mistake, since I hadn't ordered it, but it was all correct (although I hadn't gotten anything like this the first day). However, I ate it, to not be impolite, despite I don't like hot food at all. It was really hot as hell, at some point I thought I would die. There was one green sauce, which was also hot (for whatever reason) and something that looked like yoghurt (and most likely was), since it wasn't vegan.
The third day then there was this chili stuff again, but this time it suddenly came with bread (and was therefore easier to eat for me). I had some fairly good lunch, except there was a (small) piece of sausage in it, which I picked out once I saw it.
The day after that they wanted to give me another aperitif, however not a complimentary but one with an extra cost. It was some kind of big dumpling. I asked if there was cheese in it, and it was, so I refused, stating I was eating plant-based. Indeed, that didn't stop the waitress from trying to persuade be, arguing, it would be healthy and the cheese was local aso. Finally I got the chili pot again (no bread). Meanwhile they dredged some cheese on the main dish although that wasn't mentioned in the menu.
The last day was fine again.
So in total the whole story is ambivalent. On the one site some of the food was amazing (and pretty inexpensive, too), on the other site they don't pay much attention to the difference between veganism and vegetarianism.
Cons: slipshod, not very vegan-friendly