Clean Bottle's design premise seems to make sense at first glance. By adding a screw-off bottom, it's easier to clean the thing out to prevent the build-up of illness-causing gunk – or so the company would like you to believe. The problem is that it's not actually all that easy to clean and doesn't work well as a bottle, either.
Screwing off the bottom does improve access to the bottle's interior but the end cap's various nooks and crannies are hard to scrub out and provide more haven for various microbes. And despite the silicone rubber seal, the bottom is prone to leaking unless you're careful to screw it on tight.
The other bits aren't any easier to clean than a standard bottle, either. The middle section still requires a bottle brush and the top cap is as tricky as always – the region Clean Bottle really should be concentrating on if the goal is easier and more thorough washing.
More to the point, we've not once ever had any issues scrubbing out standard bottles with that same brush – even one that we'd accidentally left in a travel case with leftover energy drink for months (and yes, it was as nasty as you've envisioned).
Adding insult to injury is the fact that the Clean Bottle is disappointing to use on the bike. The thick sides are much harder to squeeze than usual (something the company are apparently addressing), the stubborn valve is tough on your teeth, and if you're a weight weenie it's worth noting that it's 30g heavier than a comparably sized standard bottle.
Oh, and have we mentioned that it's twice as expensive as a Specialized Big Mouth bottle? The removable ends do make for faster drying than a regular bottle and the plastics used are BPA-free but that's hardly justification for the other drawbacks. If you can think of a reason to buy one of these, feel free to let us know because we can't.