Sat BA 5 for last night's show. When I picked up my ticket, the box office manager told me "If I had to pick the best seat in the house, this would be it"...and I have to agree with him.
I think the front stage right banquette gets the most interaction of any seats in the theater. Actors are constantly making eye contact with you, sitting/lying at your feet, whispering to you, offering you illicit substances during the club scene, etc. Helene and Anatole frequently sat at my feet, and both Josh Groban and Lucas Steele made prolonged eye contact. A great seat for No One Else, Sonya Alone, and Dust and Ashes...literally every song had an awesome view. The spotlight hit our row quite a few times as actors sang. Whew!
I got a dumpling and letter. I don't think there's any set pattern of letter giving--I was really into the show and had a dumb smile on my face/grinning at cast members when they looked at me, so that probably boosted my chances.
If anywhere on BA stage right is available (particularly BA 3-11) and in your price range, I would definitely recommend. Incredible experience.