Which ipad to choose! Urgent

Hey guys, I will be buying an ipad today. I have been searching and searching..
I have been reading on forums and I got confused more than ever before. I know this thread is one of the lamest topics and it really depends on you and your personal preferences when it comes to choose an ipad. Anyhow..I just need your opinions.
I am a medical student 6th year and will be finishing this year. So I will need to watch a lot of KAPLAN videos and download a bunch of PDFbooks, e books etc. (pathology, pharmacology...). I am not going to take notes on it or use it as a game console... Just reading my textbooks and watching some Kaplan videos. and have some medical apps..At first I wanted to buy an ipad air, but as I have a MBA 13' and iphone 5s.I really thought I want to wait til october when it comes with touch id. because I am so loving it. and I want also the wifi to be upgraded in the next ipad (probably ipad air 2). And I will also give all my money for it to be cellular and around 32-64 gb

So my main concern is, I have a limited budget. I have 3 options.(all 16gb)
1) ipad mini. the price where I reside is in total 280$ (taxes included). They want to get rid of their stock. So they are selling it to very good price.(even in a normal apple store it is 299+taxes = 330$) So I save a bit money. And probably with that money will get more apps and ebooks. But is it soooo hard to read on ipad mini?

2) ipad mini with retina. Well pricing is 450$ (including taxes) So there's an amount between two. But is it really worth it to have a retina mini while theres a bargain for ipad mini 1st gen?

3) ipad air. pricing is 520$ ( including taxes) you know it. Big blah blah..

Thank you in advance. Everybody!

 

but there's an amount going on between 1 & 2? why retina may i ask?

 

I had no problems concerning the processor.. A5-A7 I dont care that much, because everything works perfectly on normal ipad mini I can wait for 2 milliseconds more for an app to open up. ..but the resolution.. I am just curious if my eyes will burn or hurt while reading on ipad mini 1st gen.. I dont want to throw the money away just because 1st gen is cheap..And I dont want to throw it away after 5 days of usage ...

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anyone else, another opinions?

 

Please keep in mind that i am going to buy the new ipad air when they release the newest one in october so. I dont want to just throw it away if i buy an ipad air now .. Thanks

 

yes, because I love the touch id and wherever I read about ipad air, they say it is not revolutionary yet evolutionary...
Theres no touch id, no wifi upgrade, no gold option (which I LOVE) so thats why I wanted to go with the cheapest in the market. and also thats why I am a little bit confused..


for your answer ... And if it is hell of an experience to read on pdf I am going to buy and dispose it at the end of the year

 

thank you all, I went to the store and checked both retina mini and mini itself. for me as a non-previously-ipad-owner I didn't see much of a difference, yes it was shiny yes it was more crisp when letters were too small. As you might imagine I went for 1st gen. And it is fabulous. I am so glad i saved the money