It depends for me too. For Magnum, I usually sit about 2nd or 3rd seat. (I've been in it so many times I never bother to wait for the front seat.) MF in the front was absolutely incredible, but after riding S:ROS (SFDL) in the front and back, I wish I'd gotten a ride on MF in the back. For S:ROS, I like the back by far. That first drop is so intense in the back, and it just makes the ride so much better. Inverts, I absolutely love the front seat. Although, I did like the back seat on DD (intense), it wasn't as good as the front.
Jman