The reason I suggested you stick with a laptop is because the functionality of the iPad is not anywhere near that of a laptop with some type of word processor. For example, saving, sending, printing notes is far easier on a laptop. You don't have a native file management system on the iPad, and this can lead to issues if you do a lot of saving, transferring, etc.
Also, carrying an iPad + BT Keyboard is essentially the same thing as carrying a netbook or something similar like a MacBook Air. You might as well go with the more robust option (laptop).
Just my $0.02. I think a laptop will save you time, headaches, and you'll be able to do a little more than on an iPad.
As before, If you absolutely have to pick between the two iPads; I would say go with the iPad Mini and save some cash to pay for a BT Keyboard down the road.
This is really personal preference. I use iPad w/ BT keyboard for just about everything portable, including note-taking. You can organize folders in your email, use email as a way to back up and/ or get your stuff to a PC linked to printer. For writing a lengthy paper, PC probably better, especially if you use a citation/reference management software package.
You can get USB adapter for charging port ( at least for the older larger non-lightning port) , then back stuff up to USB flash drive through adapter ( I have not done this; colleague has). As long as your library or student center has PC's w/ printers, you could make this work. As others have said, it doesn't quite stand alone, but with some minimal (yet reliable) PC access, it goes everywhere else pretty easily. I prefer it.
Having said that, the poster who commented on combined size of iPad + keyboard is also right. I still prefer to even larger laptop, but it can get hefty. So hefty that I will switch to mini and sell iPad 3rd gen (now Limited Edition!) from March release). Since I do have PC all day, every day @ work, mini wins big for me - for reasons many reviewers (including Gruber) have described.
Good luck - you really can't go wrong. If I could give you one piece of advice, it would be to purchase directly from Apple. Returns are easier (without restocking fee) if you decide it won't work, and exchanges are equally simple if you decide a different Apple device might suit you better. I swapped 16gb i phone for 32 gb after a week; did same w/ iPad3. Be sure you know return windows (ipads and phones are different- laptops might be different still). As long as you know what you can do within what timeframe, I can't recommend Apple store strongly enough. Customer service is amazing.