I have been using some good VPN's over the last years, mandatory for me was no-logging policy, otherwise I do not even consider a VPN a real one.
All tested on W7.
VPN4ALL: good provider, quite cheap if staying below 50GB/months traffic (not an issue for me). Speed ok. Quite stable and very easy to set up. Some servers are not P2P allowed.
AirVPN: one of my favorites. Excellent support, no traffic limit, very convenient, many servers around. I have read of some DNS leaks and disconnect problems around, but I did not face them. Client is not installed, it's portable.
BolehVPN: just a step behind of Air, simply because it messed up a bit my adapters configuration when installed. Speed ok, support a bit less quick than Air.
Those 3 listed have the limit of a single account at same time.
Private Internet Access (PIA): great stuff. Inexpensive, great client, enough servers. Speed ok. A big pro is that you can connect up to 5 devices with the same account.