NordVPN or ExpressVPN… the never-ending battle! I would prefer the first one. Being a user of both two providers I may claim that NordVPN has better applications for mobile devices. Besides, its Kill Switch is easier to toggle. On the other hand, Express VPN has better router configuration and would be extremely useful for those who need a VPN for gaming.
Actually, Nord and Express are the best for sure. Their functionality and service cannot be compared with other paid or free VPNs.