Hey Richard, I've got a bottle of Speed for you if you want it. PM me your address and I'll shoot it out. Gotta mail some Christmas presents out today anyway.
If you've tried Poli-Seal before GPS, I would compare Speed to Poli-Seal in cut. I have never tried GPS or any other AIO; these are the only two I've ever used. I stuck with Poli-Seal because it was easier to use and these cars did not require long protection, so ease of use and cut was the only thing that mattered.
I ONLY do AIO services if the client is selling/trading in the car. I mean, they only save $30 for me to use Polish instead and then Opti-Seal, but $30 for a car you're not keeping is a better idea.
I can't imagine getting a monthly maintenance client (that would be awesome), and I wouldn't let anyone leave without a separate layer of protection, which I would then use Polish first. Polish/Opti-Seal combo is my #1 best seller and $ maker. I don't even tell people about AIO services until they mention selling/trading in the car. Other than that...I sell them on the #1 combo.