There are few real use-cases for any commercial VPN which claims to sell privacy, they are generally snake oil. The one possible exception is to get around geo-blocking, and in that case you just want to go for one with the most numerous and reliable servers in the location you want to appear to be visiting from.

For privacy, the gold (and imperfect) standard is still Tor, and even then you are at the mercy of the owners of the exit node. Freenet and I2P are also interesting.