I *definitely* want a pair of these. But I've never tried Supras on. I know I'm an exact men's US 10 in Vans - how does Supra's sizing compare to Vans'?

I haven't had a problem buying my exact size. I have the Vans Authentics in a 9 and just bought the Supra Vaider in the same size. The leathers and synthetics are going to stretch. The TUF Supra's will pack out from the inside, making a little more room if they happen to be just a little snug. If your feet are still growing I recommend buying a half size bigger. These are expensive.

I own a pair of Vans and a couple pairs of Supras. I wear a 12 in both but I have some Raider Highs (Supra) in 11.5 and they fit decent, moreso because they're worn in now.