(I searched, but couldn't find anything relevant!)

I've got a good deal on one of those hard-sided bags which is he maximum size for BA's hand baggage, but before I pull the trigger, how practical is it for travel? At the moment I tend to use a 55 x 40 x 20cm (the old Lufthansa max size) or even a smaller soft-bag.

I guess my real question is "does it fit in the overhead bins?" I'm not too bothered by the E-190s out of LCY (I'm guessing it won't fit there anyway) but will it go in the A3XX short-haul bins, or will i end up checking it most of the time anyway (so I may as well stick with the smaller size and a 'personal item')?

Supplementary question, will I be one of those people who annoyingly uses up all the bin space and irritates my fellow passengers?