Have a similar trip next month (15 days in Italy) for my wife and I. Traditionally, we'd pair an Andiamo JG-48 (checked suiter) with a duffel. However, that suiter is pretty heavy and we have one segment (EasyJet repositioning flight) which is 20kg per bag.

So, I just bought my first hard-sided piece (an eBags EXO) which we'll pair with a large RedOxx Aviator Bag. With a 30% discount, the EXO (larger one) came in at $125 or so and it gets great reviews. It's not as light as the Rimowa (the EXO is about 9 lbs) but, at the price, it's a reasonable cost way to experiment with a hard-sided bag. If I like how it works, I'll decide whether to upgrade or not.