^^ I don't think there's really any difference, especially since I have seen the exact same pair of boots sold by different stores under different names.
I like to use splint boots when I'm going to work on circles, sidepassing, pivots, etc.. For trail riding and moving cattle, I don't like to use anything. Depending on the horse's stride, I might also use bell boots. I sometimes use back boots if the situation calls for it. The only time I really use SMB type boots is when I'm running barrels/poles etc. (or working them).
It all depends on how strenuous the activity is and how great a chance there is of legs bumping each other.
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