If you don't know who you can trust to provide a trustworthy proxy service, then there's a lot to be said for choosing a provider who can already MITM a good chunk of your traffic even before you turn on their proxy.
As I see it, "[i]f you don't know who you can trust to provide a trustworthy proxy service", you distribute trust among multiple providers, such that they must collaborate to pwn you. That's the basis of Tor. And you can do something similar, albeit far weaker, by using nested chains of VPN services.
As I see it, "[i]f you don't know who you can trust to provide a trustworthy proxy service", you distribute trust among multiple providers, such that they must collaborate to pwn you. That's the basis of Tor. And you can do something similar, albeit far weaker, by using nested chains of VPN services.