When choosing between protocols to connect to, consider how you are using your VPN. PPTP is known to be fast over wi-fi; however, it is less secure than L2TP and IPSec. So, if security is important to you, then consider using either L2TP or IPSec. If you are connecting to a VPN for work purposes, then your employer will most likely have a preferred protocol. If you are using a hosted VPN, then ensure that you use a protocol which they support.
They even offer the most generous simultaneous connection count, with six simultaneous connections through their network, where everyone else offers five or fewer. NordVPN's network isn't as large as some of their competitors, so if you're trying to obfuscate your tracks, you might want a company with more servers. Otherwise, this company is clearly providing a winning offering.