The Mrs. and I were discussing this after seeing it last Thursday, and I'd say you're about right with that age range Scott. We have nephews that are 3 and 5, and I know it would be a bit much for them, at least I think it would. Overall, we didn't think anything was "too" graphic, the simmerin' Anakin scenes probably being the worst. Otherwise, I don't think there was anything worse than what kids see in other movies (and other Star Wars movies)...limbs a flyin', lightsaber battles, and blaster shots. There is a bit more "main character" type death, instead of random clones, droids, or stormtroopers biting it.
That being said, we went to a 1 o'clock matinee, and there were a fair amount of kiddos there...with their parents. They probably ranged in age from a baby (which I don't understand) up to jr. high and beyond, with several 6-10 year olds in there. No one seemed scarred for life from it though
. My wife was actually kind of paying attention to the movie for that, as so much hubub was made about the PG-13 rating...but she didn't think anything was all that bad, aside from Anakin burning.