The Biotip is a great place for Vegans. Imad (the Owner)is extremely friendly. The 'normal falafel is not Vegan, as it contains a yoghurt sauce and one with mayo, but on request he can make you a delicious vegan falafel with hummus and an aubergine-pepper sauce, which makes it the best falafel i've ever tasted... some non-vegan friends told me that the vegan version is even better than the normal one.
All ingredients are fresh, and you really feel it it the taste. The falafel are big and filling. The normal version costs 7.- CHF and has falafel, salad, tomato and a couple of peppermint leaves (which surprisingly blend really well with the taste). The deluxe version (which I suggest) also has slightly fried vegetables with it (pepper, courgettes, aubergine, leek, broccoli, potatoes, etc.) it costs 8.80 but it's really big and nothing less than delicious.
The only negative note is that it is only open monday to friday over lunch time (10.30 AM - 2.30 PM)
Cons: Open only for lunch, open only during the week, Limited seating place