When I first read they were going to do multiplayer in ME3 I thought it was going to be horrible, but now that I have played it, I have to say it is quite fun. I havent bought any of the packs with real money, there is just no need to because you can get so many points just for playing on silver and gold. I agree that the ME3 ending is just wrong, but I thought I read somewhere that their lead writer had left the company to go work on movies in hollywood, so maybe thats why the ending is the way it is....
I play on the PC so hopefully the DLC will make it there and be free like the previous ones, the new classes sound interesting to play!