I've tried the VeePN extension for Firefox, and I think it's one of the better VPNs. Its main features, such as hiding my IP and blocking adverts, really help improve my privacy while browsing. The connection speed was also stable, even when I was streaming videos or accessing previously blocked sites. I also like that they don't keep logs, so I feel more secure. While there is a paid option for full features, the free version is good enough for everyday needs.