Empty the main body is approx 14" x 8.5" x 3", or 35cm x 21cm x 8cm. Stuffed you would end up with a bit more depth I am sure.

That's a hard one as I am not sure that any airline is really consistent on new restrictions themselves and they may change again. This is not even the size of a large purse so would "probably" be allowed, but you should check with your airline.

It would fit (as the interior size is 13"x7") however you should have a protective, neoprene sleeve over the netbook for some protection. Depending on the covering may make bag slightly too small to your needs.

seems folks have been skipping this question -"ergonomically better" is a tough one.

Shoulder bags are typically asymmetric to hang without twisting - I suspect that a symmetrical bag that can be worn over either shoulder may allow you to rest one shoulder or the other but may not hang nicely.