Which MP is better?

[POPO Sandh]

BeamMP or KissMP?

[Stinkiest Pinky]

depends on what you prefer, beamMP requires discord verification and more red tape
KissMP is entirely up to you, client controlled and user hosted. BeamMP seems to be more active but a lot of people would prefer to stay away from discord and any tencent owned IPs in general.

[Doc]

Its been over a year since discord was involved in the beamMP login. BeamMP is much more fleshed out and has drawn the vast majority of players/communities. I particularly like the CARP community that adds a full economy/career mode and 2Fast Racing for regular events and massive help in my modding projects.

Kiss seems targeted at a few friends making a quick mp session to play together.