Lacking any visible storesign, this restaurant is really hard to find. And it's not really worth looking for in the first place.
There is no real atmosphere and the waiters are unfriendly, forgetful and slow. They literally turn and walk away while telling you the day's specials. Everything about each waiter just screams "none of us should be here right now!"
The food is really weird and half of it is cold when it's not supposed to be (e.g. cold spaghetti and cold grilled veggies). Most of the buffet is unspectacular at best.
Also, apparently it's not quite clear whether this really is a VEGAN restaurant at all, or so other reviews tell me in hindsight. The (horribly designed) menu card does not indicate whether everything on the buffet, or only part of it, is vegan. I may or may not have a night's worth of stomach cramps in front of me. Having been told that "Terra" was a vegan restaurant, I am very annoyed to have this happen.
Without even searching, I have seen FOUR regular restaurants in Bairro Alto today that advertise vegan options. It's NOT the case that you need to visit the abominable hippie hellhole that is Terra. Spare yourself the pictures of Deepak Chopra on the walls and just go eat somewhere more convenient, more tasty, more authentic, and less expensive!
Cons: Worst staff in the world, Bad food, Horrible location (practically hidden)