Choose one that fits your needs, and is in good condition. You don't want to start dealing with changing components right after your purchase. Bergamont looks like a good deal. Just make sure that frame is not cracked or dented badly. Check it when the bike is perfectly clean. Rear triangle, and around the bottom bracket is a pretty common place for cracks to appear. Good luck with your choice, and what an awesome idea to commute on a bike!