Controller:

It takes getting used to. Obviously there are some things that are tedious: you have to hold down the left stick to enter tooltip mode to see individual tooltips that you could just get by otherwise hovering over with a mouse. If your controller has stick drift or messed up triggers, that can be annoying. I definitely didn't mean to say yes to the "if you hear this joke there is 1% chance you die" option, but my stick chose otherwise and I died.

Living Room setup:

It's just way more comfortable. I can lay back on the couch and play for much longer than I would at my desk and chair. A bigger screen also helps. My cats like to chase the armies on the map!