I've developed a slow leak in my RR tire, it matches my slow leak I've got in my LF.
I've been poundering putting Slime in all four tires, but have never used it or know what drawbacks it may have. I know Fix-A-Flat's drawback is that it turns to an amonia smelling liquid, real nasty stuff.

Anyone use it or have comments about it?

Nope never used it. Not sure what the downfalls are of the slime. I do know "fix a flat" has some safety concerns for service techs when it comes time to change tires. I do know that for the slime to work you have to deflate the tire completely remove the valve stem then insert the slime and re install valve stem and refill the tire with air. I do know as well that the bicycle tubes with slime work pretty good. My younger son kept getting thorns in his bike tires and kept getting flats. After we put in the slime filled tubes no more problems.

Never even thought about it.

I'm going to try it in my 2 left tires. If they hold, I'm going to go ahead and do the right side.