I know this has already been said more or less, but just bringing up a new point.

I have a wheelset with formula hubs, and one with Dura-Ace hubs. In practice I don't feel any difference. I have noticed a much larger change from a simple change of the tires.

I'd say Formula are perfectly fine, invest extra money in a wheel build from a good local builder who will help you true/maintain them. Get butted spokes and a good rim. And, decent tires, at least for the front if you're a skidder.