This is a great vegan restaurant in the centre of Chiayi. It's pretty easy to find, with a big sign in English on the outside. However, there is no English on the menus, and the staff speak no English. Luckily the locals are very friendly, and the local schoolchildren there were very helpful! We ordered 3 dishes: a curry, Pineapple fried rice, and a cold vegetable bowl (similar to Korean Bibimbop) and shared them between us. Every dish was unique and delicious, and came with red or green tea (they were cold, and much sweeter than you might expect), a mini fruit bowl, and some sort of sweet rice soup. The portion sizes were perfect by European standards, though slightly bigger than is typical in Taiwan.
The restaurant looked pretty clean, but they ask that people clean their own tables (and they only have paper napkins, so one wonders how clean the tables actually are...) It looks like a cafeteria, with tiny paper napkins, laminated table-tops, no tablecloths, etc.
From a western perspective, the restaurant was very cheap (just under £3/$4 per person), but apparently this is considered 'Moderate' by Taiwanese standards.
Overall, this is a great place to eat in a meat-dominated culture. My two dining guests were both non-vegetarians and loved the restaurant nonetheless, so even if you're with non-veg Taiwanese, this is a great option. I'll definitely be frequenting this place on my visits to Taiwan.
Cons: No English translation!, Ambiance needs improvement