All the animation studios put out very similar movies
Pixar vs DreamWorks:
Toy Story / Small Soldiers
Antz / A Bug’s Life
Monster’s Inc / Shrek
Finding Nemo / Shark Tale
They had a pretty good rivalry there, but I think they both feel secure now. Sony are the new kids on the block and they’re ripping on everyone:
DreamWorks vs Sony Animation:
Madagascar + Over The Hedge / Open Season
KFP (au) vs Sony Animation:
Happy Feet / Surf’s Up
Fox Animation is the only other company I can think of (they did Ice Age and Robots), which I don’t think rips anyone off. Pity they suck so bad.