If it matters to you, Brent's stuff is the same formfactor as the real thing. I believe you can swap card for card with a real neve 1272..
I have a pair and they work great for me. I have not really dealt personally with any other preamp company besides email. I have dealt with BA for almost a year and they are great people.
I have some of their new 312's too. They all work great for me.
I recently did my own little informal test with BA 1272, BA 312, Sytek, Ward Beck and an Ampex tube pre. Nothing definative, I just wanted to hear the difference and I did. They all sounded different. The 1272 sounded more different. 312 and WB were very similar. Both seemed to saturate quickly on the attack and smoothly decay.
BA stuff always sells when it's posted on ebay.
Cheers, RD