The upgrade to DAC3.3 will give you the same sound quality as the DAC3.5VB, but you won't have the new display, you won't have a set of analogue inputs, but I can't remember what happens with the USB input vs the ST Fibre input on the new DAC. There would be too many chassis changes and display change to completely upgrade from a DAC3 to DAC3.5VB, hence the DAC3.3.
