i have done some comparison of a lot of different products, side by side
i have not found one line that does it all, and i have found a lot of good stuff out there - much better than the choices we used to have
for cleaning wheels, P-21s is the best - you have to be careful about leaving any on the wheel, but it is the easiest to clean with - other stuff does a good job too, but needs multiple applications to do the job - i tend to think they are all the same chemical (lye), but in different strengths
on aluminum non-painted wheels, Rejex has proven to be the best so far at protecting - that is what it was designed for though, so this is no surprise
on painted wheels, Rejex or other similar polymer compounds (Meguiare's NXT, etc) seem to have about the same effect - all work very well at keeping brake dust manageable - Rejex is a bit easier to apply though
on leather, hands down, it's Leather CPR - i'm not a big believer of "Wonder-Goo", but this stuff is amazing (thanks ron)
on vinyl and plastic, i like the finish of the Meguiare's, though it does seem to need more maintenence - 303 and STP Son-of-a GUN also do very well at both cleaning and leaving a pretective shiny finish
on plastic windows, NOVUS has stood out above the rest - they make it in different grits - i like "2"
on rubber (other than tires), i again like the Meguaire's - we call this stuff "gorilla snot" around here - it has been, by far, the best at maing that black rubber look black and without a glossy finish (more of a semi gloss) - do NOT use this on vinyl or plastic
on tires, this is highly subjective - it depends onthe finish you want - i don't like shiny, so i use the above - if youlike shiny, there are quite a few out there, but i haven't tested many of those
on paint, this is a tough one - every wax has it's own specific look and ability to cover scratches - the polymers do a really nice job of protecting, and goe on easier, but don't shine as well as waxes - which one to choose is dependent on the color of your paint too - different waxes work differently with light - you kid of have to play with this one and see what you like yourself - because i have been showing the car, i have taken to having my car detailed every 3 months, and in between i am using a compound that is not available to the general public (at least not that i am aware of), so it's no help - if i can find a source, i'll post it - it's not cheap though
in the upcoming issue of 9 Magazine, there is a DIY guide to car detailing - it gives the DOs and DON'Ts of detailing - should hit the presses monday
hope that helps
