Well, I personally would not recommend reading on an iPad. It's heavy, it's big, it's backlit, etc. The only advantage for me is that you can have reading apps from all different ebook stores so you are not restricted in which store to buy from (iBooks, B&N, Amazon, etc). The iPad Mini might be better since it's smaller and lighter - I might have to steal my husband's iPad Mini for a while and test run it as an ereader.
I am not sure how your book exchange works - does an "exchange" mean that you're swapping books you already own? Because ebooks with DRM can not normally be swapped or shared so be aware that once you buy an ebook, you can't just give it to someone else. Sadly, one of the downsides to ebooks is the lack of ability to share but that is to prevent piracy.
But perhaps you are merely buying each other books? This is how buying a Kindle book as a gift works:
Amazon.com Help: Giving and Receiving Kindle Book Gifts
I can not say for other stores since I don't use them.
There are a lot of advantages to ebooks themselves, though whether or not those advantages outweight the disadvantages is really down to personal preference. For me, I love the device itself... I have a Kindle Paperwhite and it's small, thin and lightweight. I can hold it easily with one hand or even put it down on the table while I eat and not have to hold anything open. I can carry several books in this one small and light device, which is ideal for travel but also means I can own thousands of books without it taking up space in my home. Though the iPad is bigger and heavier, I imagine some of these advantages will still apply.
I also love being able to set my own font size and type. I never loose my place in a book anymore by forgetting what page I'm on or the bookmark falling out. I can buy and access books within seconds from the comfort of my couch. Before buying, I can read samples at my leisure rather than in a book store. I can dog ear pages, highlight and make notes in books without feeling like I'm ruining it (and I can easily access those highlights and notes at kindle.amazon.com). I still have access to library books, in digital format. I don't know about iPad but my Kindle has a built-in dictionary so I can merely highlight a word and the definition pops up. I can quickly and easily find any passage in a book by doing a search for a key word or phrase. Lots of ebooks are cheaper than the printed versions and there's lots of bargain deals and sales - like today is Cyber Monday and
Amazon have over 2,000 ebooks on sale! I've heard that B&N does not do as many sales like this though and I've seen a lot of disappointed Nook users who were looking forward to all the specials only to find out it's mostly Amazon who does them. B&N do have a
Cyber Monday Sale going on too, but only included 50 books. The good news is with an iPad, you can enjoy books from either store.