Rental Reimbursement is an optional coverage that you can pay for, in the event that your car is in the shop due to a covered accident, and you still need to get to work or perform your daily tasks. There are different limits that you can choose from to be properly covered when renting another car. Rental car coverage can add up quickly after an accident, and this additional coverage might be worth the extra cost after an accident.
I have had Progressive for years and have never had any trouble. My car got plowed into by a deer, and Progressive was reasonable to deal with. Their rates are also about the best I can find. We bundle in our home insurance (through some licensed third party) and save even more! Our rates just actually went down this past 6-month period which was a pleasant surprise.