I read an article, but now cannot remember where, describing a process where the author and his crew visited Dolby labs.  The facility had a state-of-the-art listening room where A/B comparisons could be done of their DVD-quality lossy format (DD 5.1) versus their new lossless format (TrueHD).  They then visited DTS labs and repeated their listening experience comparing their DVD-quality lossy format (dts) to their new lossless format (dts-HD Master Audio).