The side view seats are pretty inconvinient, so say the least. They are literally at the side of the stage, and if you're on the right, you'll most likely have the musicians and/or the drum set block your view of singers pretty much entirely. I haven't sat on the left, but there you'll probably have the piano in the way. I can't recommend them. If you're gonna spend that much money, go for the full view. Perhaps see if any of the usual discount codes works (Theatermania or Broadwaybox), they do for most shows for 15% off.
Main dining room and bar rail seating are pretty much equally good. Bar rail seating is better for people who would rather keep to themselves if you're going by yourself. In the main dining room you'll likely get to chat with the people at your table, which I think is really nice. You never know who you might sit next to!