I did not watch "The Passion," so I can't comment on it.
Unless you don't watch movies in general, I would highly recommend it. I was teaching a Sunday School class right before it came out, and had to research the technicalities of what Jesus went through with the flogging, etc. I found that the portrayal in the movie was spot on to the research I did, as brutal as it was. For me, the movie was much more of an experience than a film.