Shared hosting or cheap VPS?

[ZiNgA BuRgA]

Similarly, someone can abuse I/O performance unless the virtualising platform somehow allocates a guaranteed amount of disk time to you.  I haven't heard of any which does this, though since I don't run Xen, KVM or similar, I wouldn't know.
Or they could just abuse the network too.
Or the host could be crap, be down all the time, and the physical server be totally unsuitable.

Same thing with shared hosting, except there's even more scope for users to abuse the server.