Is the larger screen and higher resolution of the 15" MBP compared to the 13" MBP *that* much easier on the eyes. Would there be noticeably less eye strain if looking at the screen 4 to 8 hours a day. They say the larger the screen the more productive you are ... makes sense. Higher resolution shows a little more detail too I realize. Is this all worth it enough to choose the 15" over the 13" I'm wondering.