I have both this and the smaller Silca seat packtool roll.
While I like this pack, it tends to get a bit unwieldy and difficult to prevent conflict with my legs when pedaling. It's possible, but I have to take and frequently tighten up the roll to prevent it from spreading out.
So, while it's probably better than an equivalent sized seat pack that would hold the same stuff, I'd like to see better velcro to hold it in it's rolled up position.
The Boa connection to the saddle is nothing short of brilliant, however. Nothing else cinches the pack up to the seat as tight as does this boa arrangement. It is also much simpler to connect than the typical saddle velcro arrangement that requires kind of an awkward two handed drill to get the tails up and through both saddle rails.
I also like the tool roll set up. You can put stuff down on the ground without losing parts or getting them full of grit and dirt.