As background, I've owned the iPad 1 and upgraded that to the iPad Retina when that came out. I love the iPad as a lightweight device to keep me connected and use it to read (news and books), surf the web, do email, watch video, and track tasks and projects.

For me, I've found the iPad mini to excel at all these tasks. In particular, as a device for reading books I've been thrilled with it  due to the low weight. It fits comfortably in your hand and you you can read for extended periods with little discomfort. With the regular iPad, the weight is just enough to be uncomfortable to hold in your hands for extended periods.

Where I was worried was how it would work for email or web. In both of those usages I found no problem with the size of the text and being able to effective read my email or surf the web. Occasionally, I would pinch the screen the screen to make the text bigger but I often do that with my regular iPad. 

One area that other reviewers have commented on is viewing video. I had used this with Netflix and Amazon Prime Video. I don't notice the screen resolution difference between the retina display on the full iPad Retina and the iPad mini. I do find the smaller size somewhat less appealing for watching video but not so much that I would not buy a mini.

The one area where it might be noticeable is with drawing programs, such as the App Paper, that use the screen for drawing. I don't do this regularly so I have not seen that but if I was using the iPad heavily for that function I would test it out before buying.

My buying advice, if you plan to do a lot of book reading (Amazon Kindle or iBooks)  I would definitely get the mini. If you are using the iPad as a universal device for reading, email, web surfing and more it is fine and you save about $180 dollars over the regular iPad. My only hesitation would be for those that do want to do drawing or video, in that case I would test it at the store on both versions and see what you prefer.