You will need to do the thinking and the calculations!

As has been said, you have to work it out & make the choice. My parents had a motability car, and I know that all they had to do was to put fuel in, which you already know. Being in their late 70s, they decided it was a good deal simply for the lack of hassle. My mother had a stroke a couple of months before the 3-year contract ran out, and while they were in the process of choosing the next one. My father bought the outgoing one, because after 3 years he found it was ideal for his needs (Peugeot Partner Tepee).

He paid a reasonable price for it - it wasn't cheap, but not top price either. It had less than 20,000 miles on it after 3 years, and he knew it had been properly looked after, never misfuelled, and with all the niggles sorted. For him, it was again a good deal.