maybe... but more mf ALWAYS means better chance to get magic items, magic being magic + rare + set + unique.
When the "item spawn event" happens in the game, it looks at what spawned the event's treasure class (tc), (a monster, chest, etc..). The tc's are a long list of rules for what a monster can drop.. The first roll decides if its going to drop gold, an item, a rune, a charm, a jewel, etc...
MF only applys when it decides to drop an item. It has NO effect on gold ammount, on the number of charms or jewels you find
Specificly the treasure classes that decide weapons and armors are a small list of items that qualify for "weap48" these are just a simple list of item codes that "weap48" stands for. If the game decided its going to drop out of "weap48" then it rolls to decide wich item code out of that list it will drop. Once it finds the item code it's going to drop, it then rolls to decide on which quality the item will be.
It rolls in this specific order: unique, set, rare, magic, supperior, normal, cracked
Your MF% ONLY works in this part of the item drop proccess, which quality the item will drop as. It rolls to see if the item will be unique or not, if it is supost to be unique, but no unique exists for this item code, it will drop a rare item. If it wasn't supost to be unique it rolls for set, and if it picks set and no set item exists for this item code it will drop a rare. If the item code has two set items for that item code then it will roll to see which item it drops, your MF has no roll in that roll.
It keeps rolling down the line untill it finds one that rolls true, or it gets to the end of the list at which point a cracked/damaged version of that item code drops.
As you can see, once you know how the game works, the more MF the better since the first roll is for unique and thats the one your after.