Here's the official quote from HTC:
HTC is doing something new and pretty cool in the coming days: we'll be releasing an "early access preview" of our ICS upgrade for the Sensation and Sensation XE. This will be limited in scope (just a few hundred users and only in Europe) because we’re still scaling up back-end resources for general availability worldwide, and our hope is people will play with it and enjoy getting used to the ICS experience with Sense. We’ll be doing similar previews for other devices in the future, too.
I don't know about you, but I say: good job, HTC!
[Phandroid]