It was a MSR Miro-Zoid that I got on sale at Sport Chalet for $100. It was 2.5 pounds (counting all stakes and string). It was light due to its small size, not material. It was regular coated nylon. The fly was absorbing moisture and slowly leaking in large swaths- not on seams, which I had sealed. Could easily have been ultraviolet deterioration. This also happened to another tent fly I had used for many years. It is a shame, to me, that manufacturers do not offer replacement flys alone. I do a lot of high altitude trips. Once in a klutzy moment, actually fell on the tent and bent the poles. I also have set it up under branches, used fires near it - generally abused the poor tent. It had been my main tent for about 5 years - probably had a couple hundred nights out. Also had it on coast hikes - I am not sure what repeated salt exposure does to a tent.

I now have a Tarp Tent Moment. Have not used it yet. I hope it lasts a few years. I am rather hard on gear, and the TarpTent seems a bit more fragile.