Yeah, I tried that stuff and gave up on it. It gums up the valves so it's hard to put air in. It seals up minor punctures, which is fine, but often you don't even know they happened; so little by little the sealant goes away. You will have no warning that the sealant is almost all gone; but the day comes when you can't keep air in the tire any more, and you're probably not prepared.

Worst of all, I've never been able to get a patch to stick over a puncture if there's slime in the tube.