Been using tubeless tires for 4 years now, at about 4K miles a year, with NO flats. I have, of course, worn out a number of them, but if you run the Stan's sealant in them they don't leak, can be run at very low pressures, and of course no pinch flats as no tube to pinch! As for weight, I am currently running the Continental All Mountain 2.2 UST tire at only 650 grams total weight. This compares favorably to, say a Smoke/Dart 540 gram tire with an 180 gram tube = 720 grams. The one drawback is price at about $65.00 apiece. But once they are on your bike you can forget about them until they are worn out and ready to replace! The only thing I do is sometimes raise the pressure up to 60 for road miles preceding the dirt, then drop them down to between 25-40 Lb. depending on how rough the trail is ahead.