Interestingly enough for anecdotes, I've had a VPS running from the Dallas datacenter, and haven't had any outages (that I've known about) since I signed up a year ago. I've been more impressed with Linode that I even was with Slicehost.
I have another server with Slicehost, and it's been down once in the past year. Overall I'm somewhat more please with Slicehost. These are the two linode issues that affected us:
