There's good and bad to both, but if there's a press box I'm in there. I have to have accurate stats, and I do a better job up there because I see better. I also like sitting up there because I can get work done on the laptop during the game instead of doing it all afterward.
One factor that nobody has brought up, however, is the condition of the field. If you're at a stadium with that new AstroPlay turf, the yard lines are easy to see. if it's a mud pit, you're better off on the sidelines.
It's definitely a personal preference, but there are several reasons I prefer the press box:
1. It's easier to keep stats, especially if the field is in good condition. On a long pass play, I can spend my time figuring out the yardage and writing notes instead of sprinting down the field before they snap the ball again. It's easy to tell how many yards were gained by watching the refs, and I've never had an issue identifying a ball carrier. If you don't see who gets the ball on the handoff, wait until the play is over and see who gets up last.
2. Getting started on your box/story during the game.
3. Watching plays develop. Whoever wrote that its easier to see receiver routes on the sidelines, I don't get that. Why do you think head coaches are wearing headsets? it's to talk to the guys upstairs who actually can see what's going on. You see everything from the press box.
4. You get good insight in the press box sometimes, too. The one I'm usually in has an assistant coaches' booth right next door, with about a 1-inch wall in between. I can everything they say (scream), and have often picked up things from hearing them.
5. Picking up trends. Some things I've been able to get from sitting in the box that I wouldn't have got on the sidelines: a) how many times Team A ran out of the shotgun and their effectiveness in that set; b) noticing that Team B rotated 9 different offensive linemen to keep them fresh.
6. While you're standing on one sideline, you can't see anything on the other team's sideline. Up in the press box, you can see that the starting quarterback for the other team is getting his ankle looked at by the trainers.
If I have to be on the sidelines, it doesn't bother me. I'm able to keep accurate stats on the sidelines just as well as in the box, and you do get some up close things you don't get in the box.
On a side note, a couple people mentioned that on the sidelines they get explanations of calls. What more do you need explained than seeing the ref giving the signal for holding and then watching them march off 10 yards? In a 15-inch game story are you really going to spend much time explaining referee calls? If a call is big enough to warrant that, you can get a pretty good idea of what happened through interviews.
So, after all my points, and the points of everyone else on here, what's the conclusion? Do a couple games from the box, and a couple from the sidelines and see which one you like best. there's no right or wrong way to do it.