I recently moved all my php sites to a new server, about a month ago, and had previously used VPS.net for my jsp/svn/etc.. server for quite a few months.
Running tomcat and sql + a few other things have used up almost all the memory on my java server, so I was thrilled to find a mail from vps.net in my inbox today, stating that they will upgrade all nodes from 256 mb ram to 375, and add 200 mhz cpu :D
on VPS.net you create your own virtual server which is made up of 1-18 nodes (1 node = 256 mb ram, 400 mhz cpu, 10 gb disk). So it’s very easy to make new machines, or upgrade an existing one by adding more nodes (then just restart the virtual server).
The server has been extremely stable, fast (the site your on now runs on a single node) and only restarted once, the website it runs is being monitored and have not had any downtime. This is by FAR the best virtual (or even dedicated!) server solution I’ve ever tried, and I would absolutely recommend it for anyone who needs a virtual or dedicated server. 1 node is just 20$ per month, there are no sign up fees and you can cancel at any time (1 node will be able to host a good amount of http/php/mysql content).