I'll post my thoughts/experience here, just in case anyone else is interested.
I bought my ticket Wednesday for this afternoon's show (gotta love being able to buy in advance!) and it was in the front row, on the side. I'm not sure if all the rush tix are in the front row or not, but I'm kind of thinking they might be since they're a bit obstructed in some scenes. I'd read elsewhere that this problem exists up to a few rows back too, so I guess it's not a bad deal at all considering the price. Defintely worth it, despite the couple parts that were pretty obstructed (while there are obviously several scenes in the classroom that are obstructed by desks, it didn't really bother me unless someone was saying something and they were obstructed, which didn't happen often enough to make it really frustrating or unbearable).
Good luck getting tix. I think they're only on sale through the 30th...not sure if they'll still have them (or some sort of different policy) after that, or if they'll discontinue it, since the show is selling so well. If I didn't have so much stuff to do, I'd be tempted to buy a ticket to see it again this week, just so I'd know I could get another visit in (though I suppose there's always standing room).
But when did New Hampshire become--Such a backward wasteland of seatbelt hating crazies?...I mean, only 40 people actually live there. The others are just visitors who come for the tax-free liquor and three inches of novelty coastline. John Hodgeman on The Daily Show (1-30-07)
And yet, I'm too lazy to go change some of them. 
