I've been riding on solid rubber tires for over 2 years now and I thought I'd give you guys my review and experience. The tires themselves are cheap Chinese garbage I pulled off scrapped Ofo hire bikes. The Ofo company went bust a few years ago and the yellow bikes ended up at the scrap yard to be picked over for parts.

>Pros:
-Doesn't feel any different from air when on flat surface
-Never get a puncture.
-Can ride over anything without worrying.
-No maintenance at all.
-They've lasted me two years so far and are holding up fine.

>Cons
-Can't ride off-road. As soon as you're on grass or mud it becomes impossible
-Have to occasionally pull out the nails and glass that get embedded into the tire.
-Can't mount high kerbs at speed unless you want to buckle the wheel

Overall I'm really happy with them and I can't see myself ever going back to air. Clearly there are limitations but for city riding with glass and nails all over the place, these tires are great.