Of course, switching to any other layout will "reset" your speed to almost zero at first, and it could take quite a long time to reach the same speed you had with Qwerty.
In 4 years when everything has been converted is touch, you'll wonder how you ever managed with a simple "read only" display.
The sad thing is that MS could have made Win8 touch-friendly without changing everything and ignoring all known usability research; all the touch-friendly stuff could easily been added to the traditional UI. Think about it: they could add bigger buttons, swipe up/down for kinetic scrolling, tap and hold for right-click or tooltips, a resizer-blob in the lower-right corner, some multitouch gestures for quickly organizing windows and so forth (bonus points if two users could use different apps on different windows at the same time).
Instead we have... two totally different UIs, one of which is no more touch-friendly than it was before. Plus, to slow down development they told developers "oh hey, we're gonna make you learn a totally newï set of APIs too."
Beware of the Turing Tar-pit in which everything is possible but nothing of interest is easy.