Hi Steven, I have the current Haut-Brion and had the previous Haut-Brion in my home for a couple weeks while I was waiting for my amp (thanks to Don Better). I think it was the previous version with the global feedback but not sure. I cannot remember which model I had for that short time.
At any rate, you get a superbly designed amplifier with still affordable war-time tubes (!). And this model has Lundahl output transformers (!), which are fabulous. You certainly get your money's worth here.
I think Art Dudley really nailed the differences in his review:
http://www.stereophile.com/content/listening-110-page-2. I will supplant the closing of Mr. Dudley's review, however, and add that I do have experience using this latest Haut-Brion with 100db horns and the experience is always engaging and often thrilling. You are not going to make a poor choice whichever version you seek out.