I play most of the time SOLO. I farm over and over Acts 1 thru 3. After all this time (since the start of the game) I have never found a godly or "end game" item. The MF system just feels broke and un-rewarding.
I can go weeks before a Legendary drops and as I stated earlier, not once has it been a great item. The best item to date was some belt I sold for 2 mill. The other part of the MF system that sucks, it seems too inconsistent. Can't tell you how many times I have killed a Elite or Champion with great MF and I only get Blues...... it's like the MF system is broke, all that matters is the 5 Stacks of Valor.
Also, there is no sign that MF improves "quality" of items dropping. When I farm Act-1, I put on ALL my MF gear and being 22 lvl Paragon, with 5 Stacks, I am well over 325% MF. I get a item lvl-63 in Act-1.... now I know they are really infrequent in Act-1, but I still had my hopes up as I am running with over 300% MF. Well, I ID the weapon (or armor) and get very disappointed. Garbage.... just sold it back to merchants.
I could go on and on with other examples where I believe the MF system is seriously flawed; so I will just end on that note. MF system in D3 really sucks!