I have one of those cheap polycarbonate 1 litre water bottles kicking about amongst my gear. I bought it from a well known outdoor retailer a couple of years back. At the time I was unaware of the alleged stories about polycarbonate bottles releasing Bisphenol A (BPA) into the water the were holding. There are various scientific groups showing varying results as to whether the polycarbonate bottles are safe, so I decided to avoid it for now and retired the bottle to a different use, and I'm not saying what that use is. (If you google the subject you will find conflicting reports. Some groups say they are unhealthy, some groups argue this isn't true. For now I think as individuals we have to interpret this as we see it.)
So I decided to find an alternative.
Now, like many people, I bought a 1 litre Nalgene bottle. I have only one gripe with the Nalgene bottles, the price. They are great bottles, tough, reliable and BPA free. But I decided to look for an alternative for a second bottle rather than the Nalgene.
After a search around various sites, I came across a Tritan 1 Litre Bottle on the website of a Internet based retailer most people will have heard of Field and Trek. The bottle cost (as of May 2012) £3.50 plus p&p compared to around £12 (can be found for less if you shop around) for a Nalgene.
There are some differences. Firstly, the cap is a little difficult to hold onto compared to the Nalgene which is more gnarled. It also feels and looks cheaper in quality. But that being said, it was around a third of the price. I've used it for a few walks and it has never leaked and is just as easy to clean.
The Karrimor has one advantage and that is the plastic funnel in the bottle opening that can be removed for cleaning.
And of course, it's made if Tritan which is BPA free.
So dependant on your stance on the BPA issue this may be of consequence or not. Regardless, to me, it gets the job done.