I own four simulators and have tried many others. (In fact I may be selling one of them soon) I believe G2 is the best when it comes to truly simulating an aircraft's aerodynamics and physics. G2 will also give the you most advanced abilities to adjust settings and aircraft parameters (weight, aircraft dimensions, etc.) If you can go the money, the G2 is it - $200! Some fliers believe AeroFly Professional is best for 3D flying, but I can't comment on that as that's not my style of flying. FMS is OK and it's free. However, FMS will teach you little about landing and nothing about ground handling - things that are sort of important to beginners! The planes in FMS sort of skate along and don't roll on tires when on the ground.

It's the most expensive, but I believe RealFlight G2 gives you the most choices in it's configuration and the most realistic simulation of flying a model airplane from taxi to touchdown.

(PS, there is a big difference between RealFlight G2 and RealFlight G2 Lite. G2 Lite is a rather limited, stripped down version!)