B.B.
I took my son who is five and a half to see it a few weeks ago. He enjoyed it and wasn't bothered by anything, though there were some make-you-jump moments.
I thought it was okay, cute enough, but not great.
Commonsensemedia.org is a fairly good website for info on movies and help deciding what would be appropriate for specific ages. The will give a summary and list anything that might be objectionable or beneficial.