The reason I usually fly the Free Server #2 is I dont want to be bothered too much. A little more professional atmosphere. I would fly the ATC server more if the places I wanted to fly to were open.
I fly all over using the routes of American and American Eagle in the same aircraft type used on those routes.
MD80's, 757, 737, 767, 777
EMB145, ATR 72, CRJ700
I do use FS Passengers and start where my last flight ended. Makes the realisim a little better.