What are some of the best VPN providers?
It's going to depend on a few things like where your locs are and what you need it for... and how important customer service is to you. Consider posting some more details and I or another expert can maybe give you some suggestions. I will tell you I'm not a fan of AT&T from a support standpoint - just too big.
We use Ringcentral. Not the absolute best, but it does a good job. Economical and great customer service.
There is no "best" system/provider!
There is the "best" system/provider for you, the individual company that meets your needs based on an exacting analysis using a best practice approach.
How would you know unless you did a needs matrix and then your research?
Maybe the question should be: "What VPN providers are in the space?"