We just saw it Saturday, and didn't find it scary, though DD is only 1 1/2 and not really scared of anything yet, the boys are 9 and 10 and also pretty much beyond being scared of this type of thing. It was kind of cute, but in our opinions not worth the wait. It seemed very short. It wasn't crowded, but took longer to walk through the queue, get into the theater, and get back out again than the movie was worth, to us. We're glad we saw it once, but won't see it again. (Just our opinions.) The bugs are "cartoony" though, not really "real" looking at all.
I was a bit worried about it because I am terribly afraid of spiders, and both my DS's (having been stung many times) are quite afraid of bees and hornets. We had no problems though.