While I thought the concept imaginative and found the movie to be very creative and funny, the dialogue was somewhat over the heads of my 6 and 9 year old kids. Despite this fact, both of my kids loved the movie and did not find it scary. They both understood the plot, even if they didn't recognize certain references that were clearly intended for the adult audiance.
Shrek The Final Chapter was a lot of fun. Shrek is placed in a difficult position and learns a valuable lesson. Along the way he learns why he fell in love with Fiona in the first place and re-news his friendships with Donkey and Puss in Boots. My kids, 8 and 5, both enjoyed it.