This is a hard choice for me. I love the fact that as you walk around Epcot decorations and lights are everywhere. I love the archway between WS and FW.
I love Osborne Family Lights at MGM, but that's all there is. I agree with one of the previous posters that said that you get hearded through the display like a bunch of cattle. There has got to be a secret to going through that I just haven't figured out yet. Plus with so many people I don't think that you get to see everything either. You are either on one side of the street or the other. You almost have to go through twice to get the full experience. Now, I guess that I should throw out there that it has been 4 years since I have gone to MGM to see OFL so maybe things have changed.
If I had my choice of the 2 I think that I would probably choose Epcot.