If you're after a light (2.1kg) carry on bag, softside is the way to go as they're generally lighter than an equivalent hard side bag. We have the 71cm version of this case, it's a keeper and comes with a 10 year warranty - and significantly better quality (our experience) than the Standbags Flylite range.
Sale price is $140, the 10% off coupon brings it to $126.
(Edited to add - do what I didn't do and check the CR (9%) and SB (12%) cash back offers - OzB badge flipped over in disgrace)
I have the two wheel version of this and it's a quality case. highly recommended for those wanting to maximize the carry on option.