I have been a premium member for a couple years now, and I find it really valuable. I don't have the biggest cookbook library (around 100 books), but it helps me to find recipes - and importantly - more effectively use the food that is languishing in my refrigerator. I figure I save the $25/year in food that is eaten (because of finding recipes here) rather than becoming compost or chicken fod.
OTOH, I find the recipe reviews/notes on this site to be useful, but not particularly detailed, and still prefer the reviews that are posted on cookbooker.com (which is 100% free, but mostly the ingredients are not indexed). I am tryng to post my reviews/notes on both sites, but the cookbooker site seems more interactive with comments/questions about recipes - which I really love.