I haven't sat in the boxes but there was a thread yesterday saying to sit house left or Lange would have her back to you. (I think that thread is on the next page.) So based on that you'd want to avoid the house right boxes. But there is some action, along the stage right wall of the set I can imagine you might miss being too far house left. John Gallagher Jr. gives his monologue next to a bookcase over there, but I can't remember how far upstage it is or what the angle was.
I saw this 3 days ago, and when I researched best seats prior to my purchase, the consensus seemed that box seats tended to miss a good amount of action. I can see why after seeing the play. In general, Jessica Lange plays to house left a lot, so I imagine that house left box seats would be better for Lange's performance. In addition to Gallagher Jr's big speech, I would also worry about not being able to see the action on the staircase from box left seats, though there isn't very much staircase stuff. I thought that Gabriel Byrne played to house right for a lot of the play too.
I guess what I'm trying to say is, if you're thinking about box seats, go with house left, so that you don't miss out on Lange. If you could do orchestra house left, even if it's far back orchestra, I think that'd be even better.
Rule of Thumb: Avoid boxes. Box seats are virtually all at least a somewhat obstructed view. Some are very obstructed.
Before Tele-charge gave seat locations over the phone, box seats were available at the box office only (as were all obstructed views) because the phone sales were guaranteed a full view seat.
When I saw the show several weeks ago, I could see that the patrons in Box left were leaning over several times.
With the staging the way it is, there is not much to be missed on the stairs or any major obstructions, as others have said. I do wonder though, how I would feel if I had to crane my neck over every now and then. The patrons did not look to comfortable.