Depends on what you are looking for. For me, systems fidelity and ability to custom design scenarios is most important, so for that I recommend Prepar3D (Lockhe

Depends on what you are looking for. For me, systems fidelity and ability to custom design scenarios is most important, so for that I recommend Prepar3D (Lockheed Martin bought FSX and kept developing it). Even multi-million dollar level D simulators don't quite do a good job at recreating the flight control feels, so I've given up on that altogether. But some features of the flight model --- things like P-factor, adverse yaw -- are better modeled in X-plane, and visually (at least out of the box), it beats the competition. But the most immersive experience has got to be Prepar3D coupled with payware aircraft from PMDG. I know real Boeing airline pilots who actually have used it for training, and vouch for how well the systems are modeled.