I have not tried all of the WordPress plugins that display popular posts, but only “WordPress Popular Posts”, “Recently Popular”, “Popularity Contest”, “Popular Widget”, “WP Most Popular”, and “Top 10″.
I used Popularity Contest and Top 10 sometime ago and for some reason I was not satisfied with them. Since I don’t even remember why I stopped using those popularity plugins and I don’t know if they are now improved, I don’t include them in the current presentation.
I recall that Popular Widget sometimes wouldn’t show any post as popular, and WP Most Popular wouldn’t let you filter categories and it would only let you select between pre-defined periods (one day, one week, one month, or all time, any other probable period excluded!)
WordPress Popular Posts seems a well constructed plugin, which, however, caused me two serious problems.
Sometimes it would not display any posts at all! (like the “Popular Widget”), although my blog is constantly visited and some posts should always be relatively more popular than others. This happened whether I chose average views or just views to be the criterion of popularity.
The other serious problem with WordPress Popular Posts was a strange tendency to have almost identical top 10 lists day after day, although I knew visitors some days did not come for posts featured on the plugin’s popularity list.
I decided to try Recently Popular and I keep using it, being satisfied with it. The list of top posts constantly changes with new posts appearing, other disappearing or taking a lower place. This plugin is alive, and it seems reliable, so far as I can tell. If you are after a popularity plugin, “Recently Popular” is a candidate you must try. According to the author it can be used also on network (mu) installations, but I have not tried it in such an environment.
“Recently Popular” returns the number of views from the current time back to a user-requested time and it does not require a stats package. For example, it can show the most viewed posts from the past 4 days, or 7 hours, 3 months, etc.
It includes a widget that supports a user definable number of hours or days or weeks or months as well as a limit on the number of results to show. It also allows users to select posts only from specific categories. You can add the widget multiple times to the same sidebar. Check this post if you can’t get category filtering to work with shortcodes.