I'm in the Not Ga Ga Over Solid Tires camp.
I think bicycles offer the perfect illustration why. For decades my ride was a Fuji road bike with 27 x 1 tires at 105 psi. I still have it but now I much prefer to hop on my full-suspension mountain bike with 26 x I think 2" slicks at 65 psi- and that's just for going around town 100% on pavement. The comfort factor in favor of the MTB is practically beyond debate, but I've found the r.r. on the much heavier bike with the lower pressure fatties to be very favorably comparable. So I'm not beat up OR worn out when I get there.
You know, once upon a time solid tires were the standard and pneumatics shoved em out of the market partly because of the rolling resistance improvement- as noted in a previous post.
I suppose if a vehicle rides like crap it would save gas... cuz nobody would want to use it unless it was absolutely necessary.
That said, I could totally get behind a compliant yet airless tire system, if only to address my impression that only, oh, 10% of the motoring public knows what a pressure gauge and air hose are for.
