Most of the VPS providers that I've seen are US based, which means 150ms+ pings, which isn't great for SSH.
Brightbox.com also do good options for UK based VMs
Given the "I'm gonna break something" feeling I get when using the Xen console on prgmr coupled with my desire to kill and rebuild VMs regularly I'll probably just stick with Rackspace in the future.
They are also providing hosting services to LEB (http://www.lowendbox.com)
They've lost my data twice in a 2 year period, but for 4.95 a month I was kind of expecting it. But now they moved my VPS to another node and all should be fine. Which brings us to customer support: it is absolutely great and they respont to tickets very quickly.
So: use for non-critical stuff, backup, and be happy.
The price was right at the time, and they have a few basic cloud-style features (so not just a barebones VPS provider.)