The only one I've used is the speed shine (won it at a car show). I like it, but don't like it on my black vette. It works well on the wife's silver monte carlo. Gives a nice clean shine and smooth finish.
I've been using their products (nearly all of them) on my C6 LMB and now on my C6 Z-06 LMB and have been well satisfied. I'd agree with the cvomment about the black not being helped all that much as that was the case with a ZR1 I had for a while. Their process deepens the color considerably and the clay bar is the best I've tried. Speed Shine and clay bar and the car feels terrific. hen the wax goes on like melted butter and the color pops. I've found the folks there pretty knowledgeable but I'm close enough I can get intyo the Tacoma Washington store. Rumor has it that Richard Griot is negotiating for a C6 orange convertible to add to his fleet.
I did use most of their products for years. Speed Shine, Best of Show Wax, Wheel Cleaner, Glass Cleaner, Car Wash, Interior Cleaner........all good stuff.
They also offer many high end specialty products I have not found anywhere else.
But after finding Adams Car Care Products here on DC, I've completely converted. There really is no comparison. Adams products are easier to work with and work better (smell better too!). Adams also has much better customer service than what I have encountered at Griots.