Flat Attack > Slime.

Patches will stick to a Flat Attack'd tube. My experience with sealant in tubes is this: Flat Attack will seal the small, annoying, pinprick punctures like those from goatheads or radial tire wire. It won't stop anything else. But perhaps most importantly, is stops flats from being instantaneous. Crossing a railroad overpass, I had to check over my shoulder while merging out of a terminating lane. As I coming down the bridge and looking behind me, I didn't see a nice sunken waterline access cover-- wham, snakebite puncture. Hit the hole at about 25mph, and could hear it hissing/sputtering. Front tire, no less. But it leaked out slowly enough that I rode a quarter of a mile or so until I found a driveway with some shade to fix the flat. No sealant in that tube, I would probably have ended up on the ground.

Down to one set of wheels with tubed tires-- they're hearty Panaracer RibMos, which are like slightly faster rolling Gator Hardshells. Nevertheless, those tubes have Flat Attack in them. The peace of mind is more than worth the 2oz per tire.