These two car rental locations are located at the Puerto Plata airport. Both companies are owned by Europcar although they are no doubt franchised to a local. I would not recommend renting with either. Regardless of the quote you get from Europcar, they will not honor it when you get to the airport and they will charge an amount that is more than double the online quote you get from the parent company or through a third party. This has happened to at least 3 people that I am aware of and no doubt more. Doing this is not ethical and certainly discourages tourists from coming to the DR when they feel that they are being scammed.
Cannot comment anything experienced on rental cars on airports here, but in general, I personally would try to avoid doing any kind of business on the airport (currency exchange, rental cars), as without doubt the pricing is not favourable compared to anything you can get outside of the airport.
One time we entered the DR via POP, and I was badly prepared, did not have the 10 USD for the tourist tax at that point. I went to the currency exchange there, and turned out that they offered the same exchange rate for USD/DOP and EUR/DOP... I just accepted it, exchanged the 10 EUR to USD and got out of the airport.
I think it's wrong to judge that people "get scammed in the DR" based on what has happened on one airport, at a company not originating from the DR (even if franchised to the locals). Unrelated to the DR, I have yet to see one airport anywhere in the world where things are cheaper than anything town / outside of the airport. I've rented cars from two different agencies in the DR for years, and never ever I have had issues with pricing or anything.