Never had any major issues with shot lag or voice issues.
Last session we had the other week had a couple lag spikes and game dropped out twice I think but that's basically it in all our time playing it I think. Other than that has been spot on.
Hopefully the server issues get sorted so you can enjoy it in all it's glory. Also tip: the best load out has you carrying 3 grenades
2vs2 invasions would be hilarious and pure chaos. Some players are absolute beasts on invasion, they just know everything, and are in your head knowing what you're doing instantly.
Phenomenal game for coop.