MD11s and DC10s are more or less the same body, but the MD11 has lots and lots of updated systems. One easy way to tell the difference is that the MD11 has winglets, the 10 does not.

The 11 is said to be a bit less forgiving than some other a/c, esp landing in non-ideal conditions. Excellent examples include the China Airlines and FedEx MD11 "landings" at Chep Lap Kok and Newark, respectively.