Two weeks ago we started migrating servers to Rackspace Cloud from Slicehost and it appears to be equivalent in pricing to slightly less expensive for us. YMMV depending on bandwidth, storage needs, RAM.
I'm a founder of a TechStars Boulder company from last summer and would be happy to answer any questions. In a nutshell, it was a great program and I'd do it again without hesitation.
As the climber/founder speaking in this video let me clarify - I wasn't referring to any of the trust issues mentioned in the thread. I was specifically talking about the focus and clarity climbing brings and how important that is at a startup. While climbing you're 100% focused on the task at hand, which is unusual in the vast majority of our daily activities. The point was simply that when working on a startup, it's important to have a release to completely clear your brain of the clutter. I'd actually say the trust aspect is overrated.