The best place to eat in KL, without any buts and ifs. (Loving Hut might be the second choice but if you don't happen to live nearby, you usually can't spare a couple hours each day just to eat.)
It's located just across the street from KLCC LRT station (although crossing the street might sometimes be a torture when it's hot outside) and it has a lot of tasty, healthy, cheap vegan food. Of course, you can also find something on KLCC Suria mall's food court (Indian food, local vegetarian adaptations, even a pizza), but what you can get there is much cheaper, 100% vegan, and usually tastier even if cold.
For just RM3.5 (about US$1) you can have rice with any vegetables and stuff you can fit on the plate (although wasting food is discouraged -- don't help yourself too much so you can't eat it all). Stuff is usually stews and sautes with vegetables, shrooms, tofu, mock meat: usually from 10 to 20 different options, usually Chinese or Malay style (deep-fried tofu in sweet sauce was somewhat weird for my taste but even it was passable, everything else was always very tasty). Add RM1 if you want a take-out box.
Apart from that, there are some relatively cheap buns/cakes/snacks, some fresh fruits, and noodles (helpings are big so don't even try to eat both noodle soup and a full plate of rice and stuff). The only thing I miss there is fresh veggie salads; there are some Chinese-style cabbages but it's not quite like fresh tomatoes and cucumbers and salad leaves...
Every month or so there is a free buffet which is not exactly as good as it sounds. Thing is the food is very cheap anyway, but when it's free, there are less options (almost no snacks and the noodle counter is closed, I think). And for those who have no money there is some free food every day (and you can also donate to that) so I don't like those days too much.
It has roof, so rain is no problem, but it's open and hence has no aircon so if you're not accustomed to local weather you might prefer eating in the malls and air-conditioned restaurants first. It closes early (I can't confirm the time in the listing, but at 1:30pm half of the stuff is gone and I don't think they cook anything after that).
Bottom line: after trying all the popular, expensive, and fancy places (Loving Hut, Simple Life, at least three different Indian restaurants) I don't want to eat anywhere else except this place. I love it.
Note that in any other Buddhist temple in Malaysia you usually can find at least some vegan food.
Cons: open place: no aircon, it's a buffet: no custom orders, no fresh salads, almost no drinks