I have not heard either of your two choices but I do own the Renaissance mk1 which replaced an Audio Research preamp. The build quality of the VAC is superior to the AR if that matters to you. I would take the VAC without thinking twice.
The only limitation I noticed on the mk5 is only 3 inputs plus the phono, so if you have a lot of things to connect you have a problem.
The only limitation I noticed on the mk5 is only 3 inputs plus the phono, so if you have a lot of things to connect you have a problem.