I got an Elite Deboyo Race insulated stainless steel bottle for Christmas.
Benefits
Keeps my tea warm for cold winter rides
Its got a built in vent, which means its easy to take a drink without having to overcome a vacuum because its not possible to squeeze the bottle
Same style of easy to remove rubber nipple as regular elite fly bottle which makes it easy to clean
Downsides
Its as a big as a 950ml bottle but only holds 550ml
there is an extra part to clean, the silicone straw that lets air into the bottle while you are dinking there is also an extra vent hole in the cap which needs to be cleaned with a pipe-cleaner.
It makes an awful racket if you have metal bottle cages.
When I want to keep my bottles cold in summer I just add Ice or freeze the bottles in advance.