That WI is very cool; I wonder if it's more competitively priced than the outrageous Phil iso hubs.
I have the WI 17t trials freewheel; it's my favorite part of my 29er.
It looks like they're running about $180 for the hub. I know people get up in arms about expensive parts, but being in the bike game for SO long, I've learned my lesson about cheap parts - they always end up being more expensive through replacing them.
I think you can go skimpy on some stuff, like tires and grips, but if you're going for an all-out sweet build - high quality parts. Heck, why else would riders like you and I spend $100+ on a stinkin' freewheel?!