While I know this varies from set to set and user xperience, if it's my consolation I too was concerned about IR on my vt50. My old plasma felt bullet proof to IR, and I've been careful with this. That said, I've seen zero IR. the set is approx 200 hours old, and with the Olympics has been tested with the color NBC logo static for hours on end. I do use pixel aping, which has mixed reviews on impact. Overall though, IR is slowly becoming a non issue/concern for me. The same applies to buzzing.
My only one concern, still to be resolved, is what appears to my eye to be a very soft picture on some 1080i HD content and SD content. Hoping refinements in calibration will help here.