This plug-in is super easy to setup and use and having NDI support in OBS to get around clunky capture card setups for two PC streaming is fantastic.
However, I've had major issues with being unable to hold consistent 60fps via NDI, even with machines well beyond what's required and a solid gigabit network. My main PC also has to be frequently restarted because after every stream, game audio goes out of sync when using the NDI plug-in. The only way to fix it is to restart.
While I do appreciate this is a free plug-in being made by a hobbyist, support for this is also virtually non-existent (though in keeping with the general OBS support experience.) The author only responds to a handful of support threads and if you have any problems with this at all, expect to be left to figure it out yourself.
I still use this plug-in (especially since the alternative is XSplit which just, no) but it still needs a lot of refinement.