Security? From what? So you can browse the web "anonymously"? Sorry, but in the digital age there is no such thing as being "anonymous".
Not entirely, no, but a VPN does offer a lot of concealing. You just have to be sure it's located somewhere that doesn't care about subpoenas, and that the service is run by people who aren't going to snoop on you. And then you have to be careful wrt. cookies, headers and whatnot.
Traffic is encrypted between you and the VPN, so all your ISP and routes on the way can see is that you're connecting to the VPN... from there on, your IP address doesn't leak.
1. Its going at 10-12 Mbps for me when I download a file using a download manager (such as IDM).
Then the guy is either using the wrong abbreviation, or hasn't configured rate-limiting properly