Well...
The transporter was serving up redbook flacs off a netbook hiding behind Al's Mac Stack. When the Modwright Transporter turned up, I added it to the system, and synced it with the stock Transporter. Outputs then went to Al's Luxman P1 allowing comparison. Not a direct comparison as we used the stock SE output, and the balanced output on the Modwright. Initial differences were more subtle when volume matched the outputs by lowering the volume on the Modright by some 10 dB.
Differences at that point under meet conditions ...
They both sounded nice to me (thanks to the HD-800's and P1 ).
Modright had a more "tubey" signature to to its output, which I guess is the intent of the mod, so in that respect it succeeded. Which signature sounds better to you, given the relative costs, is a matter of individual preference.
The mod seemed well executed, and added substantial physical mass to the Transporter.
The Transporter has a 30-day satisfaction guarantee from Logitech so you can have an extended try before you buy. It may be worth getting a system set up in advance if you don't already have the software etc, to maximize your usable time with it. that said the Transporter can be used just as a DAC as it has Optical, coax, BNC, and XLR digital connectors
(no usb as that's missing the point )
Given the prices at this level, some people are happy with an SB3 + external DAC . You could always use a tube preamp / headphone amp if that's where your interests lie.