Wolfgang:
The composition of the adhesive is about the same between the 3M 90 stuff and the contact cement in the red can (the aerosol stuff is a bit thinner to enable spraying of it, but they adhere about the same).
However! Some clever engineering types got together and came up with a product delivery method (the aerosol can) which is far and away better and faster than brushing (or rolling) the canned product onto the bits to be secured and the securing surface and then hoping that you get it all on there fast enough to make it stick before it all dries out and becomes useless. PLUS, the aerosol allows a smooth, even, THIN coat, whereas the can-and-brush method usually makes for an uneven, thick-and-thin coat which can cause bumps on the surface of the vinyl being applied.
You've got about 10 minutes after the first contact cement is rolled or brushed on before it starts to become too dry to use, and then you have to apply more to re-activate it and go like hell before it dries out again and so forth.. If you're good and know how to work with the canned stuff, great. Most people opt for the aerosol.
Even with the aerosol, I prefer to wet both contact surfaces, wait about 2 minutes and then start to apply the parts to be able to move and stretch things around before they fully set up and become less move-able. Seems to work for me.
Remember, campers! 2-3 good, wet coats on both contact surfaces to properly adhere carpeting in a Speedstah!!