I've had the OG AB-1006 since the day it came out in '77, and it is indeed an awesome sounding record - just listened to it last night, in fact.
Just received the UHQR today and gave it a listen. I find the UHQR to be superior sonically in every way, ultimately being so much more PRESENT in the listening space; the difference is not small or subtle, you don't have to 'listen for it'.
I would say that if you love 'Aja', have good sound gear and don't mind shelling out the dough, it's a no brainer. It will sound like you've not heard it before. I just wish it was also available in a less fancy packaging for maybe $100, but I can understand Chad wanting this series to have a special presentation.
Also got the 2-45's of Jethro Tull's 'Stand Up' today, which is not UHQR, cost $65, and does not have fancy packaging (though the stand-up is there!) and sounds superb.