Multiplayer is fun and HAAARD.
Just reached Wave 8 with some randoms using an Adept with only an Avenger. It was hard, but effective. I gained four levels from 20 minutes of Singularity+Warp.
I'm going to use my time in multiplayer to boost my readiness so I can see that other ending. I didn't have the option for green on my normal run through. I'm like 800 points shy of it being available.
Currently, I'm trying to decide on which of the starter weapons I actually want to use and which would be most effective. I intend to either carry a single heavier weapon or two handguns.