Here’s a site that lists the uptime of VPS providers. From my experience, Knownhost is solid (although pricier) for a VPS and they currently have a 99.983% uptime listed. They are a managed VPS provider, but they also added an unmanaged option via RocketVPS. Uptime is one of the major factors when picking a VPS — along with RAM, bandwidth, and CPU priority.
http://www.hyperspin.com/en/ranking.php?type=2&i=10&d=90&s=10
I recently tried to install Confluence 4.2 on an Amazon AWS Free Usage Tier account and it was the slowest wiki that I’ve ever seen. The CPU throttling on the micro instance account and the lack of any swap RAM are the main culprits. I even created a swap partition using these instructions: https://forums.aws.amazon.com/thread.jspa?messageID=219055. Startup is around 15-30 minutes if the java process is stable enough. Browsing through the wiki or even posting a new wiki article takes minutes to complete.
If you are seriously interested in running Confluence, I recommend Linode VPS. I was able to run Confluence just fine on the $19.95 monthly plan. The CPU is much faster (order of 10x) than the AWS Micro tier and the disk performance is equally fast.
tl;dr – Amazon AWS Free Usage Tier is too slow for Confluence 4.2.
