Jim, to give you much the same answer I gave Matt Haywood:-
They are very different beasts and "test" your abilities in two different ways.
- FS2crew provides you with a full virtual crew. The FO does all the things an FO is expected to do. When he's the PM, he does all the PM checklists, when he's PIC, he does all the PIC thing (and you are expected to do the PM things). Passengers do not feature in the FS2Crew world. The cabin crew "look after the passengers (announcments and that's it. It doesn't have "real" passengers like FSP does.)
- FSPassengers turns things around and makes your flying necessarily passenger oriented. Yes it has virtual crew, but they don't do stuff to aid you overly as a pilot (sure, you can turn on "Cabin crew look after the passenger automatically, but that just makes them serve food/drink as soon as you turn off the seatbelt signs) You are graded, and "paid" on the flight experience as seen by the passengers.
In theory, it would be possible the run both FS2C and FSP on the same flight (you'd want to turn off one of the two's sound). FSP will make you think about the flight experience a lot more, planning journey times and fuel loads; arriving at the gate within a few seconds of schedule and with naught but your reserves. FS2C will make you a better pilot in command, following the checklists and interacting with the FO just like they do in real life.
Now, as an owner of both, I get more use out of FSP, but I bought FS2C for the default 737 recently (so I can use my PM setup with it) and I'm using it any time I'm in the B738 now, and remembering why I loved it in the first place - the workload drops out through the floor with "someone else" doing half of everything.