I ran Mr Tuffys 1993-1997. I was getting a flat tire every 10 miles from goatshead thorns, the liners fixed that.
Then a break from the bike.
I started riding again 2008 and again put in Mr Tuffys. No problems with cuts.
Then I got a new bike and started having flats again. I put in Mr Tuffys, no more trouble.
When those tires wore out I put on armadillos. At first I had both the armadillos AND liners, then I decided to just try the armadillos. The only flats I got were when the presta valve broke.
I decided a few years later that I was tired of always being at the back (or being dropped and getting lost) on group rides. I put on a lighter tire and got an extra 1mph which was enough to let me keep up with my ride buddies. The tire I was using is no longer marketed, so I am trying out Conti 4000's. OK so far.
It took me a while to learn that it helps to avoid punctures (regardless of your tire/tube/liner configuration):
... avoid riding over grass or unpaved areas
... don't ride in the gutter or hug the right edge of the road
... watch where you put your wheels
... don't ride through puddles, over leaves, sand, other debris
... stay off the shoulder if it's safe to be on the roadway (no/low traffic, good sightlines)
... find a smooth track on the pavement
... replace the tires before they fail