Nope, definitely not placebo, try it (I've owned the Ultra since it first came out, and have modeling experience from the POD 1.0 thru Axe II/KPA etc, plus I see no need for the the so called Ultra-Rez IR's (just a standard IR with a decimated tail).
I typically use the Ultra with various tube preamps, but also with the Ultra's modeled guitar preamps when I need to travel lighter etc (along with the T_CAB).
The Torpedo CAB holds 500 standard IR's, and 32 Two Notes cab sims with real-time adjustable mic positioning, reverb/room sim, tube power amp sims (single ended and push-pull EL34, 6L6, EL84, KT88), and comes with a software editor and IR capture/mix software, plus the WOS III plugin. The TN cabs are about the same as the Ultra's (roughly 2048 point), which is more than enough to capture the freq response of a cab (use a room sim for room tone etc).
The TN tube power amp sims that really wake up the Ultra's preamps IMO, but of course it's subjective.
I'd buy a AX8 if it was more flexible in it's foot switching, but alas it can't do what I need (3 looper switches and 5 scene switches without changing modes).
EDIT: I've found a way to use the Ultra's Tube-Pre for a pseudo tube power amp sim with my tube preamps which now sounds as good as the Torpedo's, and here are the details...
a) I set my tube preamp's tone stack as flat as possible (typically bass and mid up, treble down, but it varies). The Seymour Duncan Tone Stack Calc for Windows works well for this!
b) I then instantiate a amp block with the Tube-Pre, and then pick a tone-stack for my rather flat sounding tube pre. I set the Tube-Pre's gain to zero, Master Volume to ten.
c) I then turn on the Tube-Pre's power section by turning Sag up from zero, and while leaving the Tube-Pre's tone stack flat, adjust the various power amp parameters to what I need considering the gain structure and tone of the tube preamp, and the selected tone stack in the Tube-Pre (I'll look at the modeled amp's power amp settings for ideas and tweak from there etc).
Leave the Tube-Pre's gain at zero and make up gain elsewhere as needed (Level, FX Loop etc, you;ll need quite a bit).
I've tried it with relatively clean through edge-of-breakup Fender/Vox, to pushed mid-gain modded Marshall/Mesa type tones with good success.
It doesn't really bloom as good as the Torpedo's tube power amp sims, but aside from that easily as good seeing that this is all subjective in nature.
So, my bad above, sorry!
Probably placebo.
If you become familiar with the Ultra's power amp deep editing controls it has great feel and response, IMHO. Just more work intensive than the II or 2N. Although I'm sure this is a fun exercise for folks who have access to both units. The shortage of cab slots and the standard res IRs are more notable limitations in the Gen1s, IMHO, 2N would definitely be great for this. Also, I am note sure if the 2N has more resolution/length on its IRs than the Ultra, if so that would be a good thing too.