As Matt said, it is really hard to offer meaningful comparisons between such widely varying classes of lights. But since I imagine a few other folks may also have similar questions between how all the classes compare, here are a few general comments.
1. The Ultra has more output than any standard 2xCR123A/1x18650 light running on a single-die Cree (i.e. XR-E, XP-E, XG-E), including the Fenix TK10. Based on my ceiling bounce numbers, I would say the Ultra is typically ~50% brighter overall than a heavily-driven single-die Cree light. However, throw on the Ultra is typically lower than the single-die Cree class (although this depends on the reflector).
The large die surface of the SST-50 makes it hard to focus to a point, so you will find that most of the 2xCR123A/1x18650 single-die Cree lights will still out-throw it (and those with deeper reflector will significantly out-throw it). The Ultra is still quite reasonable in its throw/output relative ratio, it is just less throwy than what we have come to expect on 2xCR123A/1x18650 single-die lights.
2 & 3. The high-output/multi-emitter lights like the M2XC4 and TK40 have greater overall output than the Ultra. How much more varies on the multi-emitter setup (with some older examples only marginally brighter), but I would say most are a good ~30-60% brighter. Most of them also have a wider spillbeam due to the larger heads (although this varies), and most of them will have much greater throw (again, due to the larger reflector). Put it this way - you will certainly not find a high-output light with less max output or lower throw than the Ultra. One thing you can be sure of is much better runtime on the multi-emitter class, due to larger number of batteries typically used.
If you want to see the high-output/multi-emitter class compares, please check out my round-up review of that group.
consequences!!! 
