This section is on the far outer edge of upper left field. It's right next to the rotunda which is pretty cool (fun place to watch a game).
You could definitely cal these the worst seats in the building but it's still a good view. On most nights, these seats will be empty so if you're a Pirates fan, its extremely unlikely that you will ever actually end up sitting here.
For the money, I think the bleachers are the best bargain in the entire park. The outfield wall is low it almost feels like you're on the field with the players.

If you are staying at a hotel on the south shore, I highly suggest maybe taking the Gateway Clipper to the ballpark. It's only $5 per person if I recall correctly but it's a neat way to see Pittsburgh from a different perspective...a boat!