I've been playing this series since it was Operation Flashpoint in 2001, and there can be a lot of nothing. I don't have quite as many hours, but I've played as part of a 50 man platoon on a couple of missions where you just play against bots, and it was pretty fun, but pretty boring as well. We spent a good hour and a half just walking in a column until we made contact. That engagement lasted a total of about 5 minutes, and then a bunch more walking.
If you're looking for a good balance between milsim and arcade, I would look at the free to play Project Reality or Squad. PR has BF2 graphics, but the gameplay is stellar, second to none. Squad is still in development, but it looks good and you can get the Arma type realism without the lag time between firefights.