I use CEX a lot, although the wife still hasn't got used to be saying that I'm popping down to the CEX shop. Some great bargains, although sometimes I can find new at HMV cheaper. But for box sets CEX can be excellent and their website store search is pretty handy as well. Standards definitely seem to have been raised with the discs, I never find any scratches now.
BR audio definitely makes the most of the a/v setup, but two things frustrate me with blu-rays, firstly those that force you to watch trailers, warnings etc with limited options to skip past. Secondly, those that use JS and don't retain last played position. Other than that, I like knowing I've always got them, unlike streaming where they eventually pull the film from the subscription.