I don't "believe" any of them. My use of other services rather than staying on The Google reservation is because it's always better to not put all your eggs in one basket; The Google can clobber your entire digital life out of nowhere and with little to no recourse. Although you know for a fact that Google has all your data and records everything you do, at least there's a
chance with other smaller services that they are either keeping their word or are out of the jurisdiction of your particular law enforcement agency.
At the end of the day, there's no absolute trust towards any of them. When I'm on the internet, I'm assuming that someone with enough motivation can eventually get my data. Instead of rolling over and submitting to The Google, I at least enjoy forcing my potential enemies to go through a more complicated obstacle course.