Over the years, I suspect that GAH and ABC Rentals have gotten the best comments from forum members. Both are new RV dealerships as well as rental places. Most springs, both bring up new RVs to put in their rental fleets. They also sell off their used units after a couple of years locally, or ship the used ones back south to the lower 48 as the local market can't handle that many used RVs being for sale.
You will find a few bad reviews on any of the businesses. Somewhat like campground reviews. Or reviews of the condition of the northern highways. Just like beauty, all in the eye of the beholder. LOL I wouldn't dismiss some of the smaller rental companies, if after a through check of them, I felt they had the best rental plan to fit my needs. The two big companies, GAH and ABC, both make a lot of claims about how new their fleet is, usually two years old or less. But how many of us at home drive a RV that is two years old or less, I sure don't. Our 5th wheel is now 4 years old and our truck camper is 7 years old. One of them will go with us on our next driving trip to the north country.