Need help deciding on player for upgrade

The Wadia uses a digital volumn control via jumpers to match up the volumn and will produce amazingly detailed presentation. The Audio Aero Capitole uses an analog output with tubes to produce a warmer presentation but there are threads about reliability problems with the Audio Aero's.

Another option is a transport with a Theta Gen VIII(DAC/Preamp) which would split the difference plus has digital inputs and one set of analog inputs (RCA and XLR)

I've owned the AA and heard the Wadia. IMHO, the AA is warmer, lusher and more forgiving. The Wadia is faster, more detailed, with tighter bass. Both are very fine and right up near the top of the heap. I'd audition before purchase, however, b/c they both have a certain "sound" that may or may not suit your taste and system.