ive owned both basses, theyre both cool...my geddy lee had neck problems, presumably from its thin shape. it was constantly warping back abd forth. so be careful with that. the GL sounds fantastic with flatwounds btw.
the MM is a fine fine bass too. if youre looking to do gospel it would work real well there. very modern sound. the MM is great with roundwounds, terrible with flats! it just doesnt want flats on it, like a transplant patient rejecting a limb or something. i had mine modded so that the treble boost was dual concentric, with the top part of the pot being a regular tone knob. very handy! i also made it master volume and a panpot to blend the pickups. also a million times better than the 2 volumes
good luck with it