I run Specialized Armadillo tired with tire liners and slime tubes. I've only had this combination on for about a month, but I have picked plenty of glass and other debris from the tires. Prior to these, I had Continental Town & Country tires with liners and slime tubes. 3 flats in 3 months made me go to the Armadillos.

As far as I'm concerned, Slime has only one real advantage. When you're sitting on the side of the road doing a change, that bright green gunk makes it easy to see where the puncture is so you can slap a patch on it. To me, that "feature" is worth the extra price.