That sounds great!
Do they drive the same? Are they more prone to flat spots if they're parked a long time? If you wear the tread out, how do you change the tire (or do you have to replace the whole wheel)? I suppose the foam is made of bubbles that are actually pressurized a bit as the chemicals react during installation, so, do they gradually get softer as the years go by? Does the foam settle during installation such that the low spot is permanently heavier, or do they perhaps have to jack the wheel up and rotate it to mix things uniformly?
Inquiring minds, etc etc...