I used to go to AA fairly regularly- back when I was young and had free time-, but I haven't been there much in the last 10 years. My recollection is foul line to foul line from the ~5th row to the first few rows of the balcony are good seats. The first few rows on the main level are not elevated enough and the balcony doesn't have enough pitch so higher rows are bad. Anything behind the baskets is bad because it's pushed back from the court due due to the ice rink. I bought tickets in level 2 (lower corner/upper middle) so I'm trying to decide if I want to walk up stairs to a good balcony seat or try the corner on the main level.
Yes, a matter of subjectiveness but certain arenas change the perspectives due to sightlines and dimensions. For instance, seats behind the glass at W/R are great. You get to see all the action reasonably close to the floor. Allstate seating behind the glass is a complete disaster. You are sitting far back. Not worth it.
In BB, you wanna be where the action is, i.e., top of the key towards the paint. Why get a seat at midcourt? In football, the 50 yard line is great because most of it is played between the 20s, but in BB, all the action starts and ends within the key. I like sitting low so I can hear the sounds of the game and be right there, but it's often difficult to have a perspective of a play or foul that happens across the floor. So, it depends. Allstate arena starts with row 1, then row A, then row AA, then row BB, etc until it gets to row B. So, I think row JJ would be ideal (row 12) because Allstate sucks balls since it starts getting far far away as it goes higher. Made for the Circus and not wanting to smell Elephant poop, NOT for BB games.