For me, there are three kinds of movies: Ones I definitely want to see; ones I definitely DO NOT want to see; and ones I haven’t made a decision on, which is the majority of them.
For the first group, I read reviews afterward to see if they agree with my assessment. They rarely do.
For the second I will read reviews before, to see if my pre-judgement is fair. It usually is. Not in a “this movie is awful” way, but to see if its content or style are, as I assume, not to my tastes. I usually don’t condemn many movies as bad, I try to be fair, especially if it’s popular otherwise. Though there are a few exceptions.
For the third kind, I judge regular audience reaction more than reviews, places like here on the SDMB or the comments on io9 and other pop culture sites. I can glean better from multiple people than just one or two reviews.
Pro reviewers also tend to have a different take, as they compare movies with each other, or see so many movies they have certain expectations, which I don’t share because I haven’t seen a hundredth as many as they have.
Reviewers write for people who haven’t seen the movie. They summarize the setup and some of the plot, and give reasons why you might want to see it (or avoid it).
Critics write for people who’ve already seen the move. They discuss the plot in much more detail, as well as discuss bigger issues, like themes or how the movie fits into the actor or director’s career.
There is often overlap, and critics also review, while reviewer also does criticism.
Most of what people talk about are reviews. And a movie reviewer usually can give a more thoughtful discussion of a movie’s strengths and weakness because they have seen far more movies than the general audience, so can recognize things as being inferior or badly used more clearly than someone who doesn’t have that experience.
Movie reviews are done by movie critics, mostly. If a movie review is being done by someone who is not a professional movie critic, it probably lacks much helpfulness in doing more than saying: I liked/disliked/couldn’t care less about it.
I find there are three types of critics. The value I assign to a specific critic’s review will depend upon how the review is approached.
Critics who spend their time addressing issues in movies that I don’t find important. These people I ignore.
Critics who feel they must show off their command of the English language and their in-depth understanding of the process of film-making; the review of the movie gets lost in the attempt to dazzle us with their brilliance. These critics I read to see if something important got said amidst the attempt to baffle me with their bullshit.
Critics who address movies in a way consistent with how I watch them. They and I won’t always agree, but they at least are talking about the movie in a way that gives me useful information ahead of time. I read such people regularly when I find them. Sadly, they are not very large in number.
One such writer was Christopher Borrelli, who used to write for The (Toledo) Blade. I thought he was much too good to be buried in such a small, local newspaper. Eventually, he moved to The Chicago Tribune, but I was saddened to see that he is just a features reporter for them. I didn’t always agree with his opinions, but his writing made a movie come alive in my mind, and I never finished one of his reviews with uncertainty about whether I wanted to see the movie or not. And, in the process, his writing was very enjoyable to read.
There is also 4) Critics who hate a movie and pepper their reviews with plot spoilers, in an apparent attempt to ruin the movie for you so you won’t go.
Type 4) is why I never read reviews of movies I might go to anymore (beyond a quick glance to see if they’re pro or con), at least until I’ve seen the films.
