I really like the first one as a straight up action/adventure.
The second was awful. It fails on almost every level.
But I have the series another shot because I liked JJ Abrams and I thought part III was decent, but mostly forgettable.
But Ghost Protocol was an excellent movie. Director Brad Bird made the best one of the franchise.
And now with the fifth one, I'm hooked. Cruise is still incredibly believeable as an action leading man and by this time in the franchise, there is a strong supporting cast of returning characters. And the story looks pretty good too along with death-defying stunts.