There are definitely a lot of VPS hosts out there now overselling. It seems to be getting worse as more and more unexperienced VPS hosts start up which is causing a lot of price competition which is making more hosts consider overselling to be a good strategy.

It's not long before it could be as bad as the shared market:
5TB RAM
5TB Disk Space
5TB Bandwidth
only $5/month



I know, an exaggeration, but maybe not too far off...