The differences are not substantial but here goes. The 44 was the most musical so I call it hearing the wood of the instrument like stand up bass or piano. The other settings offered a little more detail and more resolution but it is only slightly over the 44 setting. But you tend to miss the wood on the instruments so it sounds a little faster because the notes do not decay as slowly therefore the wood sound is missing, again slightly. I used the NANO to demonstrate my DAC when I took it to someones home to hear. It was not embarrassed by any means as a transport. If you only had the funds for a really good DAC and you can get a Nano cheap in the meantime, then get the Nano. Later it can be used a s a back-up and it takes up no space at all. PLUS you can upgraded the power supply for a slight improvement also from the tiny little wall wart.
The Rega and CEC do not OS. The Rega is interesting because it really sounded good as a transport. I don't remember the differences between the Nano and Rega. My friend who had them in his system preferred the CEC TL5100Z used as a transport by a lot over the Rega. He prefers his sound musical over non-musical think tubes vs. SS. BUT again, the Rega sounded very good with our DAC which is a TUBE DAC. My friend has a Musical Fidelity (M-1 model??) which I modified with upgraded resistors, filter choke and V-Cap capacitors. It sounds pretty good unless you compare to our DAC, then it gets wiped out completely.
I am hoping to do the comparison again in another members system next month but to a better or higher priced CEC dedicated transport. Then I will know for sure if the claims that the Jays is as good or better than that model CEC.
Happy Listening.