I have to say I sort of struggle with anything past 40" unless you are using it at a much greater distance. I originally bought a 30" Dell Ultrasharp but wound up downsizing it to the 27" because I found myself moving my neck too much just to see things.
I can see it being useful if you need 4X inputs from multiple machines, or put the monitor much further away. But if you sit arms distance from your screen it just seems like a lot of panning and off axis viewing. The 34" is nice because it’s the exact same height as the 27" just wider.