Changes

The game first determines what type of item will be dropped; Magic Find has no effect on this. Once the item is determined, your MF is checked in determining if the item is Unique, Rare, etc. The game rolls for Unique first, then Set, Rare, Magical, and normal. This is why more MF is always better, since it boosts your odds of Unique, Set, and Rare. Since SuperUniques, bosses, and Act Bosses always drop at least magical items, (and have much better odds of dropping higher quality items than normal monsters do) MF there will make a big difference.

If you are tracking how many Uniques and Sets you get from item runs, you must note the durability of all Rare and Magical items to have an accurate total.