I have both cabs so I can put in my $0.02.
First off, let me say that the UL112 has been my favourite cab in the last 4 years for both electric and upright. I've bought and sold several cabs of different makers and configurations......only to realize just how good the UL112 works for me. However- and I think fellow UL112 owners will agree with me on this- the low end is not very strong on the UL112.
The AE112, in comparison is very even across the spectrum.
No peaks or valleys. The mids are not as strong as the UL112 but not as nasal either. I never thought of the UL112 as nasal until I AB-d it with the AE112. It seems more present and aggressive on stage. I still love the UL112 for the upright and it does bring out the magical mids of my Fodera 6 str. but for average gigs the AE112 is my new speaker.
I think they are both great, just a different take on the same thing. I hope that helps!