I can't comment on Simuflite's FA-50 program, but the FSI program on the straight 50 was fine. (I went to the DFW center.) About 20% of the straight 50s have the Proline 21 avionics package and if the one that you will be flying has PL21 you really should plan on going to FSI at ILG - their 50 Proline 21 sim should be up and running anytime now.
Like any other training, the quality of the training is primarily a function of the individual instructors that you get, and not the name that's hanging on the side of the building.
LS