I bought one of the new baby jogger footmuffs in stone and have used it for the first time today - I have to say I'm disappointed! I ordered the stone to go with my stone BJCM4 and it's a slightly different shade (pedantic I know!) and also seems really quite small. My son is 10 months and isn't a huge baby, but it really doesn't look like it will last him that long. There's also nothing to fix it at the top so it keeps sliding down, which in turn makes the straps go funny and makes my son look uncomfortable. That said he was warm as toast when I took him out, but overall the footmuff is a real disappointment after how fantastic the pushchair itself is.
So now I'm wondering if there's something better... what does everyone else use on theirs?