It's not awful, but definitely not the best for vegetarians. Granted it was a year ago when I went, so dishes may have changed or could even vary by night, but the options were limited and pretty basic. I remember there being a veggie pasta dish, some salad, and I ate some plain veggies and mac n cheese from the kids section.
If you really want to give it a try, go for it, and you won't be hungry by any means. But Boma, Tusker House, and Crystal Palace have way more options for those following a vegetarian diet.