Classroom Management Software

My school is considering implementing a Classroom Management software system, we are a laptop school - we promote the use of laptops in class by faculty and students.

We are still experimenting with laptop etiquette in class. Especially for our large classes, faculty would like to control the use of laptops in order to keep students focused and on track.

We are looking at three systems: Lanschool, Vision, and SynchronEye.

Our students use both pcs and macs. almost a 50 - 50 split.

Is their anyone who has experience with one of these products, or all? Any feedback on how well they work, pricing, best recommendation, features exclusive to each product would be very helpful.