Just in time for an Apple (NASDAQ: AAPL) event that's expected to introduce the world to a mini version of the hot-selling iPad today, Microsoft (MSFT -0.66%) has reportedly sold out all pre-orders for its new Surface tablet here in the U.S. and two versions in the U.K.

Low-end sales have been especially brisk. Within 24 hours of taking orders for the new tablets using a low-power chipset based on ARM Holdings (NASDAQ: ARMH) designs, a $499 Wi-Fi-only version sold out domestically. All models were sold out as of yesterday, G4TV reported .

In the U.K., limited pre-order releases of the 32-gigabyte Surface and an edition with the Touch Cover keyboard were sold out as of this morning, ZDNet reports. And that's in spite of a lukewarm response from some corners of the punditocracy.

My Foolish colleague Rick Munarriz on Sunday listed several potential hurdles for the Surface. Over at The Wall Street Journal, tech reviewer Walter Mossberg says Microsoft "deserves credit for giving Windows a new, modern, face" while noting that the software design will require some users to relearn what had been "the most familiar computing system on the planet."