It really depends on what you are trying to hide and from whom...IMO for several reasons Internet based proxies or private networks are the biggest scam on personal Internet users since AV software...!
You can hide your IP etc. from fourth parties but you still have to connect through your ISP and the proxy...some virtual networks will encrypt requests etc. but it really depends on the ISP and the proxy...
IMO The best way to be anonymous as possible (without paying for a direct pipeline to a trunk/backbone carrier (minimum $1K/month) and eliminating a typical ISP) and setting up your own system proxy...The way to go on the cheap is using the 'TOR' Browser'
Tor Project | Download