How do you propose someone actually review VPN services? All of them work, have many countries available as egress points, and are fast enough.

The only actual differentiation is in attributes that are impossible to measure from the outside: Do they log accesses? Make logs available to governments? Sell it to data brokers for advertising purposes?

That's pretty much the only difference between good and bad providers, and there's no way to tell, so in-depth reviews are an impossible task.