So I have the dual screen setup at work. Wide screen Side by side. I'm guessing it might be a total of 30 inches across? I like the setup because I can use the two screen method of fully opening an application in either/both screens. Working multiple applications together. All aplications are in my bottom left monitor tray.
Or if I like, I can stretch my Excel file all the way across both screens. Some applications just require a larger spread.
I have the large IMac single monitor at home. I played with the idea of dual monitors at home, but nothing I do at home requires multiple monitors. My screen is big enough to have multiple applications spread out across the monitor. I believe the IMac has instant access to multiple screens (which you setup), I just haven't tried it. I love the large screen for home because my eyes are getting bad and the screen is working real well for me. It's simple, large and takes up about 2/3 of my desk. Just enough room to have a few things on top. At times I wish I had an L-shape desk, but I deal with what I have fine.
Personally I love the idea of a ultra wide screen. It's cleaner.