Yeah I have one of those too, it works great, only two minor "issues" --
The straw doesn't reach all the way to the bottom of the bottle, so like 0.3 oz of fluid is just sitting there. It's really not a big deal since it reaches ALMOST all the way, though.
Also, the whole "biting" thing is kinda... awkward at first. And it must look weird to people watching you. However it really works quite excellently and doesn't leak.