Gy4, as I'm sure you've figured out, upsampling and oversampling are the exact same thing. Upsampling is simply a marketing term and 96kHz and 192kHz "upsampling" were used specifically to imply that regular 16bit/44.1kHz CD's could achieve some of the magic of DVD-A high rez formats. The timing for this marketing hype was perfect as most high-end consumers were sitting on the sidelines waiting for the high rez players to come out and format wars to settle. Interest in the latest $4k+ CD player was low as many wondered if an inexpensive DVD-A or SuperAudio CD player would better the multi-kilobuck CD players. It worked perfectly and CD player sales (with "upsampling" hype in particular) took off.
Oversampling to 96kHz or 192kHz results in a decrease in precision due to rounding errors when oversampling by a non-integer multiple; however, Im not sure this is truly significant to the quality of the sound. Usually, these products will then use another digital filter to oversample to some higher rate such as 384kHz (4x96). The truth is there are great sounding products that do this and also great sounding products that simply use a cascade of integer multiple oversampling digital filters, or even a single integer oversampling digital filter too (eg 8x44.1 = 352.8kHz or 16x44.1 = 705.6kHz).
I do think that technology has improved over the last 5 years with better off-the-shelf digital filters and DACS. Also, knowledge of implementation techniques has grown significantly (witness the growth in modders who tweak existing designs to squeeze out better performance). In the end, the quality of the sound is a function of the quality of parts and implementation (eg transport, clock, digital filters, DACS, reconstruction filters, analog stage, etc) and not the marketing hype. Youre doing the right thing in trying to cut through the marketing bs, but ultimately, let your ears decide.
