I have been using baby sleeping bags ever since my eldest was born 8 years ago. I love the simplicity of them and the lack of worry about blankets ending up over faces or kicked off.
The Slumbersac has taken this one step further and also includes sleeves, which I’ve not seen on a sleeping bag before. I’ve been using it for my 7 month old son for a couple of weeks and have been very impressed. He’s snuggly warm, even on the recent freezing nights and I’m looking forward to taking it camping in the summer as it’s finally an answer to the question of how to keep baby warm but not too hot in a tent.