I'm not sure if this is the right place to post this but I thought the information was pretty interesting.
I found a good article on Smarter Travel about a study on the percentage of awards availability to be found on the major carriers. For some, I don't think there will be too many surprises, e.g. the paltry 10.7% availability on US Air. This company performed 6,160 booking queries at the websites of 22 frequent flier programs during February and March 2010. Travel dates spanned June through October 2010; 10 long-haul routes and 10 city pairs under 2,500 miles were checked to assess reward seat availability. The company has created a guide (for the small price of $399 LOL) but there is an overview of what they discovered here.