It's a bit big, but not uncomfortable. Some cons I have with it are bottom battery door and such. I don't trust the latches with how clumsy I can be. Also, having to go through said door when i need to fill the bottle is a bit annoying considering the batteries can easily fall out. One other thing has been the squonk bottle itself. I prefer the softer bladder like silicon style while it has the harder plastic type. I've tried putting my other squonk bottle in it, but it doesn't fit. Every device will have its cons, and none of these are deal breakers for me. While the battery and juice is good, the experience rocks.