I bought a Playback Designs MPS-5 a few months back, a one-box CD/SACD solution with an Esoteric transport and a proprietery upsampling to DSD DAC and claimed "unmeasureable" jitter. When I use my Oppo or Pioneer Elite DV-58AV as a transport it's almost as good as using the MPS-5's internal transport. There IS a difference, but the removal of glare and digital uglyness seems to all happen in the DAC/clock. So, IMHO, transports matter, but the DAC/clock combination is the most important, by far.
Dave
Dave