I've been using Vapur bottles for years, and I generally like them a lot. I had no problems until I bought a DrinkLink through MD and the 1.5L bottle started leaking on me after a few months. It surprised me since my several years old bottles that I carry/use almost daily haven't leaked. Vapur replaced my leaking 1.5L bottle and so far the replacement has held up longer. I guess time will tell.
I've mostly had good luck with Vapur. 5 good bottles to 1 leaking bottle. The oldest two (and still most used) bottles are about 5-6 years old.
That said, I've seen a lot of comments on MD from people with leaking bottles. Anecdotally it seems that if your bottle is going to spring a leak, it will do so in the first 2-3 months.
It's still a great concept, and (in my opinion) one of the best designs for a collapsible water bottle. But it seems that the quality control isn't perfect, so you're taking a risk. At least in my experience, they replaced the leaking bottle for free.