II loved the first MI, which warped the TV program with Jim Phelps' true character coming out as a total surprise that kept you guessing till the end and yet can be watched over and over. 2 and 3 essentially made Cruise into a superhero, creating a role he could plod through with as much interest as a clod. While he is still somewhat of a superhero for this one, there is no question that it is best since 1.
Released from prison by a lovely agent, Hunt is immediately entrapped in some kind of web he has to figure out. The entire MI force is disavowed, so he has no resources but those of his immediate team, which includes a new techie, a mysterious diplomat, and the tough chick. It is a rollicking good ride and I will definitely buy it once the price falls. The feats are just believable enough, things keep going wrong, and it is more complicated (yet ever so close) to disaster. I was not bored for a minute, never lapsed into "some guy is just making this up" mode, and wondered what was really going on for most of it. That is success.