@evildictaitor: I can appreciate your point of view, but I happen to disagree with it highly. If you have any idea about how budgets work, then you would know that it's better to go ahead and tell a department they have to upgrade their software six months in advance. Those of us that got on the ball early were prepared for Vista when it came out. Departments were notified that software needed to be upgraded, budgets were made to take into account of those new purchases. Workarounds were prepared ahead of time. If you wait until RTM to begin the process, you can be years out with a deployment. Pre-testing allows a large environment to be aware of the problems and look at solutions should the final product not be up to snuff. In many cases, it allows us to push departments to prepare instead of waiting until the last minute and have confusion.
Should one plan on the beta to be the final. No. Although, if you have been through this long enough, you would know in 90% of the cases, there are very few large scale changes from beta to release candidate. RC is usually the polish stage.
I haven't made a final judgement on Win 8 at this point, although if I wasn't testing I wouldn't be doing my job which is preparing an organization for any changes that are coming. If I wasn't keeping up with the press releases about final decisions, I wouldn't be doing my job.
I don't know, if the information is out there, let someone post a link. In my area, the appstore isn't the answer. We have tons of "public" access computers, the idea of allowing anyone to install anything at anytime doesn't fly here. Even if it's free.