After using the iPad mini for three weeks now, I could never go back to the 10" versions. They just feel like bricks.
Here are my thoughts on the two models.
Typing:
I find that typing on the mini using the smart cover to be as to be as easy as typing on my older iPad with a smart cover. I can types as fast and as accurate. The limitation in typing speed with ALL ipads is having to switch between the letter, numbers and symbol keyboards. The difference in size DOES NOT affect this, period. I just do NOT see and issue here. When holding the two devices and trying to type, the mini is the better of the two. It is Small enough for me to hold in one hand at type with the other. in Addition, It is so easy to thumb type in portrait mode with the mini. My hands are big enough that I can thumb type in landscape mode with the mini, but it is a bit of a stretch. So if you type on a table or desk it is about the same to me. If you type while trying to hold the device (what it is intended for) the mini Wins period....
Screen:
I find the screen quality of the mini to be great. Sure a retina display would be nice, but I would NOT want it if it adds any weight or thickness. I am 48 and do not have that great of eye site. My only worry with the mini was being able to read the screen. To my relief, it just has not been an issue. I can see all of the text just fine without glasses or contacts. I can still read it fine with my Bi-Focal contacts or my Transition glasses. My biggest worry turned out to be a no-issue.
Watching videos:
The mini wins hands down here. It looks great and is so much more comfortable to hold in all situations.
Web browsing and reading:
The mini wins because it is so much more comfortable to hold.... If I can easily read the text and the pictures and video look great, then I have to ask why would a larger iPad be any better at this?
Speed:
I am sure that the A6 is faster, but I have not felt like I was missing anything. All apps seem to run smooth with little is any lag. Maybe it will not work with the next iOS update, but it works great with iOS 6...
Portability:
The entire point of the iPad is to be a portable device. In my opinion, this is why the Mini is so much better than the iPad. I find my self carrying it to places where I would not have bothered to carry the iPad. I find that if the Mini is not up to the task I need, I pull out my 13" macbook pro. Since the mini will doe anything that the iPad will do, I do not think I would have reached for the larger iPad if the mini was not up to the task...
Conclusion:
iPads are meant to be portable devices. The Mini is far more portable and will do anything that the larger iPads will do (at this time). I just do not see any good reason to chose the iPad over the mini IPad at this time. The fact that the mini cost less is just a nice bonus for me. If they were the same price, I would still pick the mini....