"The man with the gun shoots, the man with out the gun follows..."
The Falcon solahma depicted in Legend of the Jade Phoenix and other books were more "armed" than armed. Maybe they got rifles, maybe they got spears, or sharpened sticks. They probably had their old uniforms left over from their days of being useful, which probably includes boots of some type. Maybe one in each unit gets a radio. What true warrior needs more, really?
In other Clans, clearly, things were different (or not). Even the worst punishment unit in the Horses is probably quite well equipped; they probably have at least a 1:1 ratio of guns to warriors (seriously, they're probably nice guns, ok uniforms, and most importantly they'll be commanded by officers with a lifetime of training in infantry tactics). Outside of the Horses (and maybe the Vipers? they always seemed to have more infantry than I would have expected) most Solahma infantry will feel most keenly a lack of any sort of infantry training or doctrine. Sure, each individually will tend to be a competent fighter, since no warrior would neglect their martial skills, so marksmanship and physical fitness will be high, but beyond "look! The enemy! Shoot!" I can't imagine much in the way of tactics, and since most seek death, a headlong rush towards the enemy would be pretty standard.
Relative to the IS, just the fact that IS troopers would have an instinct to keep their heads down would be an advantage. They might be able to beat green conscripts with a month on the job just by dint of their individual abilities and fanaticism, but any unit of fully trained IS infantry would out fight real true solahmas.
Of course, the sort of infantry that rate mentions in the Field Manuals and deployment charts and such (Horses and Vipers mostly) will be of a very different sort.
