I see that there are lots of VPS/cloud questions, but they all seem geared towards choosing for a new project - I'm interested in switching teams.
For the last 18 months or so, I've been very happy with Slicehost. (In fact: I recommend them.) But as demand has grown, I've increasingly been having memory issues and have had to do emergency hard resets on more than one occasion. One option would be to resize the slice again, but demand seems to come in bursts, so it seems wasteful to pay all that extra money for extra memory that isn't needed most of the time. For that reason, I've been looking into Amazon's EC2.
Has anyone made a similar transition? What should I watch out for? Is it even a good idea?
Specifics: The organisation is a community radio station. The server instance runs Apache (which hosts wordpress, mediawiki and phpBB installations) and Icecast ('pimped' with Liquidsoap).
Gotcha: There is no such thing as 100% uptime. Amazon has been known to have platform-breaking issues spanning days with their EC2 service.
With Amazon EC2, you'll still be paying for the RAM you need, but you can easily scale up or down (in cost and RAM, or # of servers) to different instances with only a reboot.
One gotcha with Amazon is that you'll be very tempted to use the extra features they offer; they have a much larger feature set than other VPS providers. Once your infrastructure is heavily dependent on these features, you'll be locked in to Amazon--by your own choice, of course.