If you have a lot of spare money, by all means buy a etrto 622 bike. However, do not believe the difference will be great. There was a recent test in Bicyle Quarterly, and the difference was statistically insignificant. If like most people you only have one serious bike, use the etrto 559 bike you already have, but with fast tyres. Schwalbe Big Apple 50 mm are comfy and fast. Panaracer Pasela 26x1.75 faster still (but less robust). My own drop bar tourer has etrto 559 wheels. I then choose my tyres depending on the conditions.
Willem