The 500 level seats have come under criticism for steep angles and nose-bleed heights. The stadium has undergone improvements to alleviate some of these issues, but seats above row 8 will have you wishing you spent a couple extra dollars and didn't have to walk up so many stairs.
Never-the-less, seats in sections 520-524 are among the best in the ballpark on firework nights. These seats have a head-on view of the fireworks and you won't have to strain your neck to see them.
The first few rows in the Upper Level are sometimes called 'Premium', though they have no special benefits or privileges.