I went along to one of those sales and found the prices weren't any cheaper than in the shops. Also, the sale was meant to be at the ice rink but got moved to a place in Guterstrasse which was dark and overcrowded.
I ended up getting mine from Herzog sport in Binningen and I'm so glad I did. I could take my time, got great advice and after test-riding about 6 different bikes around the neighbourhood, I realised I didn't want a mountain bike at all. I bought a hybrid/urban mountain bike and I'm very happy with it. I even got a 3 month free service and a tax sticker thrown in.