I tried several on and here is what I found
Hopefully helpful info to someone.
Also, how tight should a trials boot fit? Snug to the point of no foot slop or is a little slop a good thing? Obviously these aren't ski boots.
Gaerne balance oiled US10 EUR 44.5
Little support
Little protection
Minimal ankle support
Feels mostly broken in to start
Hot spots from just below middle buckle on antero lateral ankle / anterior aspect of medial malleolus could become better/worse after break in period?
Just slightly wider than alpinestars in forefoot and toebox and significantly wider in heel
Heel hold dependent on buckle tightness
1/4 to half size larger than alpinestar
Feels nimble
Feels like a hiking boot
Alpinestars
Lots of support
Moderate protection
Moderate ankle support
Good heel hold only minimally dependent on buckle tightness
Might not accommodate a high instep
Feels quarter to half size smaller than gaerne
Less nimble than gaerne; feels heavier than gaerne
Feels more like an enduro boot then gaerne
Thicker sole than sidi (however under ball of foot thin enough for excellent balance, slightly better than sidi)
Well padded
Forma boulder black US 10 EUR 44
Less support than alpinestar more support than gaerne
Middle buckle cuts into anterior of ankle when flexing forward
Minimally wider than gaerne in forefoot and toebox
Instep is snug
Ankle has tons of room (swims)
Poor heel maybe better for high volume ankle
Slightly longer boot than alpinestar but not quite as long as gaerne
Cuff is one to one and one-half inches taller then gaerne and alpinestar
Last seems to fit similar to predators but predators have best heel hold for me
Sidi
Slightly less wide then gaerne
More protection then gaerne, less then alpinestar
Slightly longer then alpinestars and slightly larger overall
Less heel hold then alpinestar but more than others
About one inch taller cuff
Lots of mobility
Front of boot cuts into ankle with flexion but no buckle involvement so will probably go away with break in
Feels lighter then alpinestar, lighter then forma not as light as gaerne