Affiliate programes always look enticing because they pay large amounts of money,
but are they really, more profitable than PPC (e.g. adsense)?

I can see them working on very high volume websites, but what about lowish
volume (say 100-200 visitors/day)? Are they worth a try?

I'd be interested in anyone's actual experience, rather than just guesswork!

I prefer affiliate programs to adsense for simple reasons that,
1. You don't need $100 to reach minimum payout.
2. You can be paid via paypal.

Because of these two reasons I work hard and try to make more from affiliate programs than adsense. 

I like Adsense better than affiliates, but both sides definitely have their strengths and weaknesses. People view websites for information in most cases, rather than buying a product. This hurts affiliates, but some sites are definitely built for purchasing, which obviously wouldn't hurt those types. Adsense can make you a great chunk of money because of the way they convey their ads and the types of ads they place in their banners for you.