Two words characterise John & Joseph's: Fast & cheap. You'll pay 2,75 EUR for a full English…read morebreakfast. A cheesburger with chips is 3,75 EUR.
But be aware that the quality matches the prices. It's not bad but on the far end of acceptable. The meat tastes cheap (and it probably is), the chips are too floppy, sausages have a strange taste to them, soft drinks are served in their can. You cannot complain but you could think of a tastier meal.
The waiters, however, are great: very quick and sometimes even friendly.
Personally, I'd spend a Euro extra for a little more quality. But if you want to strengthen yourself for a night out in Benidorm or if you are hung over and need to refill your resources, John & Joseph's is a good place to do that.