Ok, not really "exchanging" ... but give my iPad 3 to wife and keep the mini for me.
I thought this was not going to happen, but I ended buying a 16GB 4G mini yesterday. Tried in the store few days ago and it's size and ergonomics impressed me. They are sold out here in Houston but by chance, I was in an Apple store when a new batch of minis arrived.
... temptation was too high and bought one.
Before I left the store, the hundreds of 16GB models were almost sold out, again, amazing!
Anyway, I previously owned a Galaxy Tab (old and new versions) and Google Nexus. Returned because device was too slow or kind of small for PDFs. So far the mini feels really good. It is big enough on landscape mode for my SQL books (PDF files) and fast enough for browsing Internet and emails.
The thing is ... the retina display is awesome on the iPad 3. However, the text is sharper on the mini, more than the iPad 2. I guess is because pixels are more compressed?
My wife does not like the mini, too small for her taste. So I have two choices: give the iPad 3 to her and keep the mini, or return the mini and buy a new iPad 3 for her (her current iPad 2 has very minor issues with volume button)
Any feedback? ... I do not watch movies or listen music. I mainly use my iPad 3 for reading PDF files or light browsing. That's why I'm so in loved with the mini's size and weight.