If I remember rightly, and this is going back 2 or so years, supa studs are the ones with the 'holes' in, so when you put them in, any loose mud gets caught in the hole (its long and runs up the side of the twisty bit(sorry, very untechnical!)), therfore not damaging either stud hole, or studs! Normally studs just have the thread, with no gap in it.
I use supastuds and still tap the holes in the shoes before putting them in. If the studholes are always clean and have cotton wool in them then supastuds are great but if you forget to put your cotton wool back in the supastuds won't self tap...this is what I found anyway.
SupaStuds are not self tapping, but self-cleaning. The difference is that they wont damage the thread in your shoe if you line it up wrong and wont wear the thread out by constantly re-tapping.
If the cotton wool has come out you will need to dig out the excess - just as you would if you were going to use a tap - but then the SupaStuds will screw straight in.
The only time I use a tap now is if the top of the hole is burred over (even then I only take the burr off) and by asking my farrier to countersink the top of the stud hole this stops most burrs anyway. Hope this helps!!