If you're not a fan of plastic (for the kids), or worried about the practicality of glass from a breakage point of view, there's another option – Pura stainless steel. It's a versatile range that's designed from infancy to adulthood – all you need to do is change the mouthpieces to suit the age and stage.
There is absolutely no plastic in Pura products – the bottles are made from non-toxic stainless steel, while the mouthpieces are produced from medical-grade silicone. Interesting to know is that Pura bottles were designed by a husband and wife team who battled to find something that was safe enough for their kids to use.
I tried the sports bottle and the baby bottle and both are easy to clean, didn't leak and were comfortable to use. As you'd expect, they're a bit heavier than plastic bottles, but a little lighter than glass. As much as I love glass bottles, the stainless steel sports bottle I tried felt more durable. I'm often dropping bottles, and nervous about breakage, so this gives me comfort.
The bottles start at R265 from Faithful to Nature.