Not sure what Mondo means, but your post made me realize most of my clothes fit better with European brands than US. I've got Nordic ancestry (tall,skinny etc)
Mondo sizing mean the number is literally the length of the inside of the boot in centimeters. That is... a boot that is Mondo 26 is 26 cm long... so if you measure your foot and see that it is 25.5-26.0 cm you can be relatively sure the boot will fit you length-wise (it may be too wide or too tall still... but no manufacturer lists those dimensions).
My only reservation with Salomon is they more a ski brand, but whatever, function trumps image.
There are plenty of snowboard-only companies that produce crappy products because they know stupid image-conscious people will buy that crap. Salomon has been making quality snowboard products for decades now.