I did my Westwind and GII initials at Simuflite Dallas as well as numerous recurrents and I find them to be very thorough, proffesional and responsive. Their instructors try hard to make both the class and the sim sessions both pleasant and productive while giving you information you can use in the "Real world" as well.
For comparison I did my Astra initial and recurrents at Flight Safety in Wilmington and felt they did an equally good job.
From what I hear Simuflite is usually the cheaper of the two providers.