303 is one of the best vinyl protectants out! More so if it's exposed to UV.
Another one I just started to use is 1Z cockpit premium. That seems to be more matte than anything I've used so far.
The 303 can be a bit on the glossy side if you do not wipe it off. if you wipe it, it goes a bit darker on black vinyl, but not shiny like Armorall (thank God).
I've used Megs #40, but went to 303 for the UV level of protection without the overpowering smell. #40 does smell like a new car at times, but to me it's too strong.
303 I've been using has been applied to dash vinyl top area (black), all rubber seals/gaskets, engine compartment, even tires!
Kind of all around good product.
Zaino also makes a good vinyl product.
Regards,
Deanski