If there is one type of mobile app that has truly earned its keep with lawyers, it is the PDF reader/annotator. Lawyers have no shortage of documents to mark up, and tablets, with their touch interfaces and easy adaptability to stylus-based (or finger-based) writing, make an ideal platform on which to do so. Over the years, an array of PDF apps have taken the field, the best of them pulling off that all-too-rare feat in the tablet world: They do what they say they will do.

The big names in this category are pretty consistent from year to year, but they’ve been steadily tweaked by their makers, gaining new features and improvements. With the recent release of an upgraded GoodReader, a perennial attorney favorite, this is a good time to look at the latest incarnations of three top iPad PDF apps. (One of them, iAnnotate, is also available on Android, though with a more limited feature set.) You can’t go wrong with any of these apps, but depending on your needs, you may go further with one of them than the others.