For serious use, the MBP is a better bet. I mean, on the iPad, I've noticed Safari crashing a fair bit, whereas the Mac takes in everything that you throw at it.
MacBook, easily. As mentioned above, the OS etc. and full keyboard would be much better to have, and the MBP is still very light and easy to carry with you. If you can afford it, I would say definitely get a MacBook.
Honestly you could get a good laptop for way cheaper than a Macbook. I would suggest a laptop over an ipad just because it is far easier to do essays and assignments and is just that little bit more powerful and practical.