Just an added expen$e that did nothing for us.
Tireliners: just as many flats as before; some caused where the liner overlapped/joined.
Goop inside tires: when you do get a flat, it's not fixable. You need to clean the goop off the tube and inside of tire. Messy!
Solid tires: Tough to install/remove. OK on supersmooth roads. LOUSY riding on bumpier roads and like riding an earthquake when crossing cattleguards or RR trax.
We use tires with Kevlar. Maxxis Re-Fuse 700x25s are out favorite.
The occasional flat is not an issue. That's why they invented spare tubes/patchkits!