For me, Dura Ace for 13-16t. Euro-Asia Imports for 17t.

Dura Ace is world class and the cheapest. What more could you ask for? This photo is from the mechanic's station of some world-class event (Germany I would guess based on the flag sticker). Notice the Dura Ace and EAI cogs.

Soma cogs are remarkably similar to Euro-Asia Imports cogs in look and feel (and font). Not sure if there is any relation between the products.