See these for reference:

http://news.ycombinator.com/item?id=1132138

http://journal.uggedal.com/vps-performance-comparison

http://news.ycombinator.com/item?id=966555

http://journal.dedasys.com/2008/11/24/slicehost-vs-linode

Still, Slicehost is certainly one of the best VPS providers.