We did it last year and had to stake out our fireworks spot on Main Street about 3 hours prior to showtime. Just be aware of your surroundings. A fight started to break out behind us, as it was crowded, folks were tired of sitting and another family started pushing their way into the area folks had been sitting in for hours. I was thoroughly impressed by the way Disney security handled it. They basically formed a human wall between us and the conflicting parties. We (the family behind us and us) did have to yell that there were small children around when the argument got heated - but Disney security swooped in before we could finish our sentences.
If you don't have to watch on Main Street, I wouldn't do it again. Watch from one of the recommended places like the 2nd level of Innoventions....