adriano: regarding kool-aid, it's an opinion sure, but not fact. Here's a fact from Phil Wood's Brent (no longer at PW, this is circa 2004):

"Please don't use Surly (ISO) cogs on our hubs. We have seen about 8 stripped hubs in the last two year, 6 with Surly and 2 with Soma. Surly cogs do not engage enough thread and the ISO threads do not match up which is why it was rough going on. I have also heard they are redesigning them, just don't know when. Soma cogs are ISO also and tend to seize, something to do with the plating they use. Plating will also tend to "pool" in the valley of the threads so it will round off our nice threads even more than others. Dura-Ace cogs are the best bet that we have played with.
Ours will be available in about two months. Thanks, Brent."