I went through 3 tubes with pin hole leaks on the back side of the tube where the divot was for the spokes. I never had that problem before with other tubes, put some rim tape on and the tubes have been holding. We will see.
On two occasions the valve core failed to close when the nut was locked down on brand new tubes and allowed the air to escape when inflated. There was no way to fix the failure. Totally useless tubes. Never again.
These tubes are good when they stay inflated. I have two, 700 x18-25 Presta 52mm fail because the stem will not lock closed. I would inflate them to 100 psi, close the nut, and air would leak from a brand new tube. A total waste. Because this is the second one, I will not purchase Airstops again. Neither Bikes Tires Direct nor Michelin had an explanation just news to them.
I have been using this 700-23 tube in 700-32 Panaracer Pasela tires on my commuter bike for a couple years with very good results. They are durable, hold pressure for weeks and last very well even though stretched beyond their design size in these larger tires. No flats so far.
I ride my Specialized Roubaix with 700x25 tires at 90 lbs. pressure. I have never had a snakebite problem with these tubes. The ride is great and I really like the smooth stems that do not eat up my pump seal. They are a little bit heavier than other tubes, but are worth it for the durability that I look for.
I keep several of these in my personal inventory because they hold air and I like the smooth stems. I need to check my tire pressure only once a week and then it is rare that they have lost more than 2 pounds. The smooth stems are kind to the grommet on my floor pump. I am sure these tubes are marginally thicker than most others, which makes them marginally heavier. It is worth it for tubes that do what tubes are supposed to do.
These tubes are very good for every day and training. They hold air so you don't have to pump them before every ride (I refill about once a week) and I really prefer the un-threaded stems which mate with my pumps without leaking while pumping. They seem to be less prone to flats compared to thinner tubes.
These are good tubes. I had read from other reviews that they hold air really well from ride to and I must admit I find that to be the case. In a week period I will loose less than 10 psi on these tubes. I don't even check anymore on rides that are only days apart.
Maybe it was a bad batch, but just went through 4 of these with flats in all after 20-30 miles on each. Rim and tire fine, replaced with another brand that I got from the shop and have about 400 miles on them with no issues. Never getting these again. Again, reviews seem good so maybe it was just bad luck but it sucked because I was riding in remote places.