One note of caution, when I was looking for a used wadia I talked to the factory and was advised that the transport in the 6 is obsolete and cannot be replaced if it ever breaks. Of course, that's pretty unlikely, but it's something to think about. The guy I talked to also seemed to think that of these choices, the best bang for the buck was the 830. (Although the 850 is better if you can afford it). I don't know about the 6i, as stated above, probably best to call Steve Huntley.