I didn't use it everyday, only those days where I had to drive through rush hour. And when the traffic is not bad, the amount they charge you is less.

I'm not sure how much it would help getting to Murray, but the traffic between Murray and SLC can get pretty bad sometimes, and it'll save you 15+ minutes on a lot of days. Plus there is the 400 S exit from the HOV lane, so if you do work downtown, you don't even need to merge over to the right.