Hi,
While I've not compared the Lampi Transports to any of the above, I do have experience with both the USB (a USB to SPIDF converter with tubes) and the SBT Transports ( Lukasz takes a Squeezebox Touch, disassembles it and provides it with a better power supplies) and I believe both share the same unique tubed output. The SBT works just like a Squeezebox product but sounds incredibly better. I've had both in my system and it is hard to tell them apart sonically. I liked and chose the USB transport because it could work with jRiver or any other Apple or Windows software. Either compared to USB directly into the DAC make a significant improvement more lampization as it were. If you like the Lampi sound and own a Lampi DAC either transport will make you very happy. Of course they will both work with other DACs as well.
While I've not compared the Lampi Transports to any of the above, I do have experience with both the USB (a USB to SPIDF converter with tubes) and the SBT Transports ( Lukasz takes a Squeezebox Touch, disassembles it and provides it with a better power supplies) and I believe both share the same unique tubed output. The SBT works just like a Squeezebox product but sounds incredibly better. I've had both in my system and it is hard to tell them apart sonically. I liked and chose the USB transport because it could work with jRiver or any other Apple or Windows software. Either compared to USB directly into the DAC make a significant improvement more lampization as it were. If you like the Lampi sound and own a Lampi DAC either transport will make you very happy. Of course they will both work with other DACs as well.