I'm actually going to say no. I literally have an ultra side by side my II while I recreate some patches.
There are 3 things that I absolutely love about the II. First, the cabs. I believe this is where the majority of the sonic difference comes from. I don't know how to test this without buying them, but I bet if you had the ownhammer and redwirez cab collections in the ultra, it would sound very similar.
Second, the "amp voicing" knob on the amp block is amazing. I'm not sure how it's changing the model, but it feels like a predetermined eq setting, like you would have on your ipod. It's great to have, but I'm pretty sure you can simulate this in the ultra.
Third, the directory of patches. Incredibly useful until I get the patches organized and settle into a a few of them. I used 7 patches to do everything I needed to do across 2 bands with the ultra.
Of course there's all the little interface things that are handy, like usb, the quick control knobs, etc... But sonically, they're not that different. In fact, some of the new modeling is in the ultra. There are several stock patches that are in both units and they are extremely similar apart from the default cabs.