If you've been to either, which if your favorite.
Put me down for Knott's Berry Farm. Besides having my #1 coaster Ghostrider and dozens of other great classic rides, they have the best food, theming, atmosphere, lanscaping, friendliest staff, everything! Just a well rounded beautiful park. I'm constantly comparing it to Busch Gardens Williamsburg since they offer the same level of quality throughout the park in everything they do, and in some cases, even surpass Busch.
Six Flags Magic Mountain - I love most of the coasters, but then that's where it ends. They've placed so much emphasis on just adding coaster after coaster(and not all of them that good), that the rest of the park has been seriously neglected and needs alot of work. All the things I said about Knott's are complete opposites at SFMM. Can't wait to ride Goliath though, but even so, SFMM will still be a very hollow park without much sole. If you were to take away the coasters, your not left with much else, and a great park in my book needs to offer more than just coasters. Just my opinion.
SFMM has the rides but no atmosphere, but there rides are not of the highest quality, collosus is a waste of time it is rough, and they never run two trains. Cyclone hurts like a mother, Batman is a clone, super is fun once,with Riddlers being their best ride. Plus there aren't that many good flat rides there. Knotss has all the atmosphere, alot of good flat rides, it has ghost rider, and is owned by cedar fair. Plus they have the chicken resaturant. I almost got sick on the food at SFMM, the pizza dragon place.
It basically seems that all Six Flags parks food is terrible and if the coasters didnt exist at these parks than it would be a waste of time.
I think the point is, MM is for big people who want big rides(like me). Knott's is a complete park, with great coasters and things for the whole family. I don't see anything wrong with having both in Southern Cal. I wouldn't give away Goliath or Riddler's revenge for anything!