Received my #240 Small Carry-On Bag few days ago, and has been carrying it since and really happy with it.
Btw, I also have the Medium Field Bag
Dimensional wise, the #240 Small Carry-On Bag is just a bit bigger.
And with the same loads; with 240, it feels a lot less lighter than when carrying with Medium Field.
Plus I can now add a 13" laptop and A4-sized binder. And a camera . . .
(Pics from the Net)