In general, I found the bag to be well made and offers good protection for the synth. The main compartment is a perfect fit for the Osmose (as it should be!) but nothing else will fit in there other than the synth (perhaps a change of clothes or other soft materials, if needs be). The storage compartment on the top of the case can fit a surprising amount. I managed to fit in a laptop, an audio interface, 2 jack cables, 2 midi cables, a few USB cables and some documents with space to spare.
I bought the transport bag because I needed to take my Osmose abroad. Although the dimensions of the bag exceed usual hand luggage allowance, I was let on two flights without question and the bag easily fits in overhead storage without inconveniencing other passengers. The handles on the top and side make it easy to mauver into place but you need to be careful taking it back down as the Osmose is a relatively heavy synth. I wouldn't like to check in the bag as hold luggage, but I think it would probably be ok (if there isn't anything fragile in the storage compartment) I was prepared to let it be checked in if the airline insisted.
