Just had an awesome run with my infiltrator in MP

granted it's not as impressive as some of you guys, but essentially I recently unlocked the viper, and I was a beast with it. Only 3 of us on a map and my team mates were not going after any of the objectives when they came up (except the killing ones). I essentially carried us all to the end of the round, went several grand over my team mates as far as points are concerned. Really a whole lot of fun I'm glad ME3's MP is not just a slap on component to the game, I was really worried when I head that it would have MP back in the day. Good to see that my concerns were allayed.

Any of you know how viable the Infiltrator is in the later difficulties? Right now I'm just rocking socks in bronze though I suspect I'll probably have to switch up my tactics and such for silver and gold.

For Gold matches you have to have an infiltrator, preferably a Salarian. They are potentially the highest scoring class, and they generally have the greatest chance of surviving when things go badly. Probably the best class in the game, at least on its own.