I have a 2012 15" MacBook Pro that I've been using in med school. I appreciate the larger screen, especially with the split screen feature. I've never had an issue with its size and it fits perfectly fine on our school's various desks.
You'll have to ask yourself if you feel you really need the bigger size, because the cost definitely jumps up. If you're fine with a 13" when using at school, you could always buy a cheap external monitor for home and have a big screen there. For me, spending that money initially was worth it and 5 years later it's still going strong.