I have 3 of these bottles and have owned them over the past 1-2 years. I use them regularly
1. On 2 of the bottles, the tab that you press to flip the straw out have broken off. This is will normal use. I have met 2 other folks who have had the same problem. I called camelbak and they sent me free replacement lids
2. Bite-valve eventually developed a small tear. This decreased the amount of water I could drink at one time as air interfered with flow of water. Again, camelbak replaced this
3. MOLD MOLD MOLD MOLD MOLD. I know regular cleaning should prevent this, however, there are many parts, lots of small crevices, the tube is hard to clean without a proper tool, and the bite-valve has to be removed and cleaned with a q-tip. One of mine had so much mold, and I was in the middle of no-where, I ended up throwing it away :(
4. Ahh, this is the kicker. I am active duty military and am exposed to unpressurized aircraft on a routine basis. As we go up in altitude, the air that is trapped inside expands and pushes on the liquid inside. If not careful, when i flip the straw, the liquid would shoot out great distances and randomly hit people IN THE FACE, thus leading to akward moments with the commanding officer
I will move onto nalgene bottles to see if they are any better.