I have only seen Mission Impossible 1 and Ghost Protocol. The only amazing thing about the franchise is that Tom Cruise is still doing it after 23 years. He looks great too.
Because besides the second movie, all these movies have been highly entertaining. Many would say number two was also entertaining I guess. It did make a ton of money. I guess the biggest reason is due to the trailer being amazing, he did all the stunts, and it is hard to find a great action movie these days that is not Super heroes.