In my experience with the beast, if you work it right, the MD-11F is pretty damn good. For a medium size market it is not too big,like the 747F, but it has legs to work a direct routing at payload. (when we had them here in PDX we could send them direct to ICN with a payload around 70 tons, which was perfect, not too much wasted space.)
With the nose door on the 747F you open up a wide range of really long stuff, but it's kind of rare to actually need to use it, and as it has been mentioned, your height is limited to 96". On the MD-11F the door is wider so you have more room to rotate long nasty stuff inside, and if it built up correctly you can pull off some pretty long stuff.
Tipping can be prevented by intelligent step-loading or use of nose tethering equipment (like FedEx and other have). Zone limitations are actually pretty generous and again, with proper knowledge, not that big of a deal. And using containers is really a big waste of space when dealing with general freight, palletizing that stuff is much easier.
One main reason I think that airlines are dumping the 742F for the 744F is sweetheart financing from Boeing, and that the airlines that can utilize the aircraft the best (UPS, FedEx are well suited for its unique nature) have already snapped or are placing their bids for them. And as one marketing guy told me once...in terms of public recognition, an MD-11F isn't quite the same as a 747F.
Just my thoughts...
is that a light at the end of the tunnel or just a train?