Well thats the strange part mate, its the hardner thats the dangerous bit and that aint used in base coat, only clearcoat, soild colour and primers (which can still be all used)

As for the price....... More expensive, but it does cover a bit better

Oh and its an arse hole to get dry (unless you have a booth with blowers) and you have to use a different spraying style, ie instead of going round the whole car coat by coat, you have to paint the whole of one panel (say 3 coats) then move on to the next panel.