Both can play DVD's, ps3 has the advantage of playing Blu-Ray.
PS3 advantages: Free online play, Blu-ray, graphics are usually better and if you've been playing PS2 then the controller will be a familiar feel. Less children with mics I find.
Xbox advantages: Online play is better, Kinect, if you have bigger hands then the controller will be a bit more comfortable and some games run smoother. Also I like the avatar customization.
If you want a simpler console to understand I'd say the PS3 because certain things about the Xbox annoy me, such as not having a few countries on their Xbox marketplace so I find it harder to play videos and to download games, PS3 I never had a problem.
Both are pretty balanced if you ask me, but personally if I were to choose one over the other it would be the PS3