I think it all depends on your motoring background, most of my life I have had a spare wheel, when alloy came in it was a steel wheel but full size, then we went to aspacesaver wheel and now a pump and aerosol. From my point of view it goes against the grain to have the latter, whilst the aerosol is ECO friedly it's not going to work with a tyre with wall damage. Then your going to be stuck unless you have relay/recover or it happens in the day time when a new tyre can be obtained.
My car was a stock model and I was not able to make a choice between the spacesaver and kit, the car came with a kit but I ordered a spacesaver for the reasons explained. Anyone want a spare kit! Theres lots about it on the forum