The PMDG 737 is pretty old, essentially being designed for FS2002 and updated since. It's still a good add-on though.
Their new 747-400 is a nice piece of kit, although I find it a bit temperamental in terms of the flight model and the soundset.
For my money, the LDS 767 is right on the money. Rock solid flight model, beautiful VC and all the functionality you could ever need.
