3rd thumbs up on the Butterfly, I've not got one myself, but Keith B showed me the workings when I was over there a couple months ago and it's fantastic!
I use UI every so often, I've got it loaded into a small A7 sized pad and that too works great - Thing is that the Butterfly is so clean and it'd be near impossible to find the gimmick flicking through each and every page of the pad
DC