cruizinrc- Heh heh, I'm not far behind you quantity-wise. I DO, however, usually keep the '84 Volvo outside these days. I use something different on most of the vehicles, generally dependent on what look I'm after or what I'm working with (e.g., the Volvo has TERRIBLY scratched paint that's worn too thin to fix by polishing). But I insist that ALL of the products I use be pretty easy to "get right".
At the moment, all except the XJS get some kind of synthetic (K twins, Autoglym SRP,
Pinnacle Creme Glaz, BF-switching to PUPP). The Volvo and my wife's A8 get wax toppers (Collinite for the Volvo, 3M paste for the A8). The XJS currently has VM topped with P21S.
Don't worry about trying something new. If you polish first, or use a "paint cleaner" or
all-in-one product, you won't have any problems. I'll bet that at least ONE of your cars would look much better with some other product. It can be pretty amazing how much of a difference different products can make. Part of the fun of detailing a number of cars is finding the right combo for each particular vehicle.