We are a diesel repair and fleet service shop, that is my main concentration. I recently bought out a garage with 2 gas techs and all there customers and started doing light duty gas cars and trucks in my shop. With that said, I have 3 tow trucks. 1 rollback, and 2 med duty wreckers ALL PAID FOR (key word). On average I tow 2 trucks in a week for my fleet customers as a added bonus of a one stop shop. Now average I tow 1 of my private customers a week as a added bonus, somtimes its because they need the vehicle delivered or picked up. Its been an added money maker for me definitely since some of my city contracts require it. Definitely for me worth it.
Some of the cons. First off the insurance for me is just an added average of $3900 a year per truck since the umbrella covers most of it besides the on-hook. Also another con is out of 5 mechanics only 1 tech and me can operate the rollback. Only I can operate both wreckers. If I go on a long tow I'm out of the shop for a wile, my service writer can handle most of the issues but most fleet supervisors want to talk to me and me only.
If your really thinking of a tow truck you have to think of your customer base and cost effective. If its worth it go for it. Worst thing though is to have to pay for a truck monthly that sits there costing money instead of paying for itself.