Personally, from when I played on a friends 27", I thought it was too big. 20" seems about right for me. If you use lots of add-ons and mostly use keyboard shortcuts it would be good though.For those that have played on both screens, can you give us some insight? Do you have to scale down on the 27? Is the 27 too big for good game play, ie, too much real estate to navigate, eye strain, etc etc etc?