A majority of the reviews complained saying the game felt "too similar to Halo" citing the look of the characters and assassination style melee moves. Others said the experience felt "very bland" with no real complaints, but also nothing to really draw them in as well. One review asked why Doom's multiplayer was worth his time when a new Unreal Tournament was due out this year. It's a good question.
Personally, I didn't love the multiplayer experience, but I didn't think it was awful. At the end of the day if you're purchasing Doom for the multiplayer as opposed to the campaign you're going to be disappointed anyway. Of course, if you like the online mode, keep playing! Just keep in mind the community may be small after launch.
Doom launches May 12th on PC/PS4/Xbox One.