I've been to the ACC several times for concerts and games. It's very clean and efficiently run. The view of the event is good from any seat in the house. The sound is excellent. Almost every major tour makes a stop or two at the ACC. Whenever Buffalo gets skipped over by a show I'd like to see, I make the trip to ACC.
The ACC is conveniently located. It is within walking distance of many popular Toronto hotels. There is also subway access. I would recommend against driving to the ACC, if you can avoid it.
The food and drink selection is good. They sell huge cups of beer, so that you don't have to constantly leave your seat to buy more. My only complaint about the ACC is that the prices of food and beer are insanely high, even more so than food and drinks at other arenas. Other than that, it's a great venue!