I own both units and can say that both have their place in the food chain. I got the Fractal exclusively for the studio. I use it for laying down guide and scratch tracks. I did not want to have to bother with setup and mic'ing my rig, and I wanted to get a produced sound with studio quality effects quickly. The Fractal does just that, and it does it fast. For keeper tracks, I bring my "A" rig into the studio and use a traditional set up with cabs and mics and the like. I have a bounty of Boogies at my disposal, so I can layer with any of them (the Triaxis/2:90 being the primary sound) or mix the fractal in if needed/wanted. I do not, nor have I ever used the Fractal live, but it is very live friendly both in terms of tone and portability....the other thing is that the sound from night to night is constant. Dial it in and forget it. Also to note, the foot controller give you every possible inch of control over the unit, making it a single unit silver bullet.
For a live situation, and considering physical condition, you can look at a few different sonic scenarios. I understand that you do not want a huge footprint in terms of weight and portability. I have no experience with the Two-Note Live product, so I will not comment on it's merits.
#1- Fractal direct - The AxeFx will sound great direct to the board and you are only lugging a light 2 pace system. You can use a monitor send (if you have wedges) for your on stage "amp", or you can go the route of in ear monitors.
#2 - Fractal Direct with power amp - if you got a hold of a 20/20 and a stereo 2x12 cab, you would not need your own mix and you would have a awesome tube power section in a lightweight package and in 3 spaces. You might also want to explore the Matrix power amp. Many Fractal users are turning to this British solid state power amp. It is lighter than the 20/20 if I remember correctly, and integrates with the Fractal in a live set up flawlessly. Many Fractal users shy away from tube power sections, especially the Boogies as they say it "boogifies" the sound of all the other amp models. The Matrix product is frommy understanding extremely transparent. I also see many Fractal users turning to the Fryette amp. They claim it is the most transparent of all the tube amps, but the weight would most likely put it out of your considerations. However, to me " boogifying" the sound is a good thing as a day without Boogie is like a day without love or sunshine!
#3 - Tri w/ power amp and effects unit - if you stick with the Tri, a 20/20 and a high quality effects unit, you can do a lot of damage with 3 spaces and minimal weight. Obviously, the stereo 2x12 would be a part of the rig, but you would have amazing Boogie tones. In terms of effects, a modestly priced until would be the TC G-Force. I notice many Tri users have on of these in their racks. Personally I use an Eventide Eclipse and don't consider using anything else. The Eclipse is a pro studio quality unit that can be used live too. Another plus in regards to the Eclipse is that since it is studio quality, I can yank it out of my rack, take it to the studio and use the same exact effects live and on the recording. I think having your studio sound live is awesome, it's like not having a "dual life".
In closing, I'm not going to sit here and tell you the the Fractal sounds just as good as the real thing...nothing ever is in my opinion. There are may YouTube videos featuring head to head comparisons, so please draw your own conclusions. BUT, in a live situation, the difference would most likely be minor. I can say that the Fractal is infinitely more versatile than the Tri in terms of tonal variations. A Boogie will ALWAYS and ONLY sound like a Boogie (THANK GOD), the Fractal is a slick chameleon, a pro package wrapped up in 2 spaces that allows you to sound like many popular amps and give you extremely high quality effects to boot.
I hope this helps you out and I hope you regain the strength back in your torn Achilles.