The arguments about how realistic the images are are not that relevant to how good the sim is to learn to fly.
The trex model is realistically difficult to keep still in the hover. I had to tune down the power a bit and make a more stable version so it flew like my x400 on a 3 cell pack. This was all pretty easy to do.
The dynamics are good. It is very much like flying he real thing.
The flying site Ade posted is not in the current version, they promise some more in the next release shortly. The scenes they have are seemless 360 degree hemispheres, you cannot see the joins, and the models crash into the obsticles.

The trex will sink right into the long grass!

I am very happy with Phoenix, glad I saved the money over reflex XTR, about a 30% saving.
dunno how much the other products are that have been talked about in this thread but it seems to be widely agreed that the top sim for helis is either reflex xtr or Phoenix.

There is absolutely no comparison with FMS by the way.