Benchmark DAC1USB vs PRE1 vs Transporter

as a 2 channels pre/pro in a 2nd system:

It will be used to drive a power amp (Ayre V3, I think the load is 10k) and will be connected via USB directly to a PC.

Pros? Cons?

- One big pro for transporter is the remote volume control
- One pro for PRE1 is the analog-in for SACD player
- DAC1USB is of course, the cheapest. (or use the $ for a good 2nd hand preamp?)

Benchmark PRE1 seems to have newer Op-amp compared to DAC1, is it true?

I have the DAC1 Pre and can say that it sounds incredible. I missed the remote volume control of my old preamp for awhile, but now that I'm used to not having it I'm fine with it. I previously had a DAC1 (non-usb) going to a Bryston BP25. The DAC1 Pre sounds much better to my ears.