Wow, tough crowd. But to be honest, I’ve not had the best luck with Slime brand sealant. I have had a little better luck with Specialized AirLock sealant, but none of those types of products are 100% anyway. In the event that the AirLock didn’t work, I’ve still been able to clean up the tube and install a traditional patch. It’s always best to carry a spare tube so you’re not trying to patch on the side of the road.
When dealing with sealant filled tubes, remember to position the valve stem at the bottom (6 o’clock position) for at least a minute or two to allow the sealant to flow out of the stem. Then, rotate the wheel to position the stem up high (10-2 o’clock) to fill. This will help keep sealant from clogging up the valve stem (and your pump head as well).
-Kedosto