Went to a Hawks game vs. the Washington Wizards. On that particular night, we were able to sit pretty much anywhere we wanted on the upper deck so we took advantage. Fans were scattered all over the place.
Any seat you choose in 411 will be about as good as it gets on the upper bowl because these seats sit at mid court. You can't really tell who is who when you sit that high up and most fans that sit up there probably aren't expecting a good view but they likely just want admittance into the game without spending too much money on tickets. The crowd noise was pretty much dead weight. Philips Arena is a fairly small arena on a wider scale compared to Turner Field and the Georgia Dome so most seats you will likely be happy with.

You can access the upper level seats by using the escalators near Portal 9 if I recall correctly. There are only one or two escalators in the building, the entire arena can be accessed by stairs if you're in the mood for a workout.
If you're visiting Atlanta for a game, there are plenty of hotels in the Luckie Marietta District nearby. But the Hyatt Regency Atlanta on Peachtree Street offers great rates and is a super nice hotel!