Yes I use it. Yes I recommend it. It doesn't replace dead-tree in many cases, but for those "I need to know some obscure info or recipe for X RIGHT NOW" cases

Yes I use it. Yes I recommend it. It doesn't replace dead-tree in many cases, but for those "I need to know some obscure info or recipe for X RIGHT NOW" cases it's worth the $20 (IIRC) per month, even if I don't touch it for 3 months. For books that I really want to read in-depth, I just buy the actual book. For bits and pieces augment-my-knowledge stuff, it's invaluable.