Its fun, they have one every night....you dont really get anything for them or even rank up as a person, But its still fun. You do however get cool medals and stuff in your "trophycase" on your elite account
I usually play every night before work anyway so i enlist in them. The last two ops i took silver.
But on a side note....We really need to get more premium members for our clan, we will never rank up like some of these clans im seeing out there with only 1-3 players playing during an match. I wonder what more we can do to get them!