The Level D i find despite its brilliance you can still jump in and do some circuits, stuff like that with not to much trouble. Its very versatile.
If the PMDG MD-11 is anything like the 747, which it might not be! - im sure it will be fantastic, but that immediate accessability might be lacking. However, it may be like the PMDG 737, and you an jump in that and do pretty much what you want !
However, if im in the mood for FMC programming and flight planning, then theres no other choice bar the PMDG

I get reasonable frames with the PMDG, excellent frames with the level D, despite my system :-?