(I posted much of these same comments in a follow-up to the review of the 3D version, when somebody asked about the 2D version, but this thread seems more appropriate.)
Both my wife and I were seriously disappointed. We felt that neither the storyline, the acting nor the scenery and effects were on par with the first PotC movies.
If they do a 5th one, we'll probably rent, rather than buy. Then maybe wait for it to hit the $5 bin, if we like it even that much.
In addition to that: On our system the menuing system was broken, with sub-menu selections appearing up in the upper-left corner of the screen, either mostly, or nearly entirely off the screen.
The navigation during play is annoying, as well. When you press any of pause, play, FF, REW, etc., a temporary "status" display pops-up at the bottom of the screen and lingers for a few seconds. So if you're watching with subtitles, which my wife and I do nearly all the time, now, thanks to poor enunciation by actors and poor dialogue sound mixing by the studios, you have to back up far more than you'd do otherwise, to give that annoying display time to time out and go away.
Since we own it, we'll probably watch it again, but we'll probably watch the DVD.
Our recommendation: Rent, maybe. And the DVD, at that. Do not buy.