I've read the Barnes and Noble edition and the Landmark edition but not the other two, so I'll just give my opinion on those.

The Barnes and Noble edition has a good if antiquated translation (Macaulay's), but this translation isn't always very readable and the commentary apparatus in this edition is almost nonexistent. I personally like the edition, but my fondness for it comes from it being my introduction to Herodotus. That said, it's also affordable, so if that is a concern, you might wish to purchase this edition.

The Landmark Herodotus has its own translation made specifically for the edition and comes with an extensive set of appendices that do a wonderful job of providing context for Herodotus and pointing out his errors, which is always necessary in a commentary on Herodotus. Still, I dislike the translation from a literary standpoint. It does not convey very well Herodotus's style of one story flowing into the next, at least in my opinion. The Barnes and Noble edition's translation does a much better job at conveying Herodotus's style, in my opinion. That said, the Landmark edition also looks very nice on a shelf, if that's a factor.

In summary, which edition of Herodotus to purchase depends on what you want from it. If you want to appreciate Herodotus as an author, the Barnes and Noble edition will do the job. If you want to study Herodotus's work as a historical source, the Landmark edition will serve you well.