Hi Supermighty,
I have never heard the Mcintosh tube preamps, but I do own a VK-50SE. The biggest caveat about this BAT preamp is that it does not exhibit an overly tubed sound. So those looking for that kind of sound might be disappointed. Curiously, many professional reviewers have said that the BAT Special Edition tube preamps are unlike typical tube preamps. It does not color the midrange nor roll off the highs. To my ears, the VK-50SE has a robust sound with excellent bass, nice combination of clarity and transparency without any harshness in the mids and highs. Overall, it is very dynamic with an authoritative presentation and 3D soundstage. I believe the VK-50SE combines the best qualities of SS with those of tubes. If you are looking for more tube-like sound in a BAT pre-amp, I would suggest you consider a VK-5i or VK-50. Both are available on the used market and allow you the option of rolling tubes to tailor the sound to your liking.
Please email me if you have any questions.