I took the Veritas Saturday and Sunday course this summer. My instructor was first-rate. He was eager to see me and my fellow students succeed. His patience and persistence surprised me. Far better than almost any teacher I have had before, from any school or prep program.
Going into the course I was intimidated by some of the topics that the GMAT was going to test. After my course I took four practice tests (following my instructor's advice) and saw steady improvement as I started to absorb the material more. When I called for home work help they were right there to help, too.
I have yet to take the GMAT, but am averaging in the low 700s on practice tests thanks to Veritas.
Pros: Covers everything you need, instructor knows his stuff
Cons: Fifteen course books are a bit much to lug around