I previously owned the standard ti-tri (sidewinder and ULC were not available for my pot) and recently acquired the bushbuddy ultra. After using it for about a week, I happily sold the ti-tri without regret. I was using them primarily in wood burning mode with esbit as backup.
My comparison went something like this:
Simplicity/ease of use: Bushbuddy
Just invert the pot stand, insert handful of twigs, and light up. In contrast, the ti-tri with inferno and floor had 9 pieces (ti-tri, inferno, floor, grate, grate holder, 2 stakes, gram cracker, caddy). On cold winter mornings, anything I could do to speed morning departure and avoid cold hands was key. I preferred the easy stowing of the bushbuddy to the more time consuming disassembling of the ti-tri. I also had to be much more vigilant about not losing the stakes or grate holder which seemed apt to disappear into leaves or snow somewhat readily.
Fit easily in my pot, taking up no extra space. Backup esbit and firestarter could be stored inside the body of the bushbuddy. In contrast, the standard ti-tri needed a separate caddy (I used a plastic cup for weight savings) which took up more space. Tightly rolling all the parts to fit in the caddy was more effort as well.
Weight: Comparable, edge to Bushbuddy
Bushbuddy weighed 4.9 oz. Caldera (with inferno, floor, grate, 2 stakes, gram cracker, plastic cup) weighed about 5.8 oz. Some weight could have been saved by omitting the inferno if desired.
Wood burning efficiency: Bushbuddy
Able to achieve a 3.5 cup boil with a handful of twigs. Did require stoking once during process but this never bothered me. Ti-tri inferno could be packed with more wood to decrease need for fire maintenance, but required more fuel overall to achieve a boil.
If you are looking for an alcohol/esbit burner that can also burn wood, the ti-tri is the clear winner. Where I live, wood is plentiful and I found one backup (esbit) to be sufficient. I was able to achieve a 3 cup boil in the bushbuddy with a single esbit. I didn't find the ti-tri to be significatly more efficient to ofset the other disadvantages above.
Workmanship/Durability: Comparable. Bushbuddy was a work of art, but required more care in handling to avoid denting. A titanium bushbuddy would be a significant improvement.
I think both are outstanding stoves.
Owning a sidewinder or ULC may offset some of limitations of the ti-tri (mostly packability). Those interested in a multifuel stove will prefer the ti-tri
For me, the bushbuddy was the hands down winner for reasons of packability, wood burning efficiency, and simplicity of design. I just wanted to offer this alternate opinion for those looking primarily for a woodburning stove.
ti-tri in woodburning mode
Bushbuddy in esbit mode
A thing of beauty