Rick, as you know, I've got both an iPad 2 and an iPad mini (both 64 GB). I use mine for distinct purposes with some amount of overlap.
I can tell you right now that if you do a lot of typing on your current iPads, you will be disappointed trying to type at the same speed on the iPad mini. I know that arcanemuse spoke the other day about the difficulty typing on an iPad. That's not been my experience. I have a bluetooth keyboard that can be used with my iPad, but I hardly ever use it. I'm actually very fast on the regular-size iPad virtual keyboard--probably at least 80-90% as fast as on a regular keyboard. Because of that I have no need for the external keyboard. That may just come from a lot of practice, patience, and forcing myself to use it. But I bet I haven't typed on the external keyboard in well over a year.
On the other hand, the iPad mini keyboard, even in landscape mode, is pretty cramped. Because one does such things when one has a new toy, I took my iPad mini into a faculty observation the other day. It was kind of fun to stroll in with nothing in my hand and then pull the mini out of my pocket. I took notes on the iPad mini for a couple of hours, and it did fine, but typing for me was a bit slower. Even in landscape mode, the keyboard is smaller than that of a netbook. Interestingly, I noticed that I was using all my fingers on my left hand, but only my index finger on my right hand--I have no idea why. For my purposes, it demonstrated that the iPad mini can be used in a pinch to take notes, but it's not something I'd want to do a heavy amount of typing. Of course, since it has dictation built in (a feature not available for my iPad 2), I suppose that this would be an option, but obviously not in a crowded room.
Of course for occasional typing, the iPad mini in vertical orientation is great for thumb-typing--seriously.
I've also preached sermons from my regular-sized iPad and have even led three wedding ceremonies with it. And yet, even with the ability to increase the font size, I think the iPad mini would frustrate me from having to turn the pages too often. It reminds me of an experience more than a decade ago, when I tried to lead a Bible study from notes I had on a Palm Pilot. Yes, I could do it, but I had to move to the next screen too often for it to be practical. My hunch is that preaching from an iPad mini might have the same sensation, although not to the same degree as the Palm Pilot.
On the other hand, for the entire past month, I've successfully taught from the iPad mini on Sunday mornings, using Keynote and presenter notes, without any major problems. I don't know, though, if there's any major reason for doing so other than the convenience of carrying such a small device. Arcanemuse wrote a few days ago about taking his MacBook Air to church. I took a Mac notebook of varying sizes to church for years for teaching. It was so liberating on that first Sunday in April, 2010, to leave my computer bag at home and instead carry the iPad in my hand and a VGA adapter in my pocket. The iPad mini is even more convenient to carry, but if I were preaching every Sunday, I'd want the larger iPad I think.
I probably said this before, but I use an iPad the same way I used to use a laptop, and I use a laptop the same way I used to use a desktop machine. I can't necessarily make that same leap in regard to iPads. I use the mini as a reader and for light teaching. It's very handy, but I imagine if I could only have one device, I'd probably choose the regular-sized iPad. I just don't want to have to make that choice :-)
Accordance Bible Software
Gear for running Accordance:
2012 15" MacBook Pro (retina) - 2.7 Ghz Core i7, 16 GB RAM, 750 GB SSD, Yosemite
2014 15.6" Acer R7-572 - 1.6 Ghz Core i5, 8 GB RAM, 256 GB mSATA, 1 TB HDD, Windows 8.1
2015 8" Toshiba Encore 2 Write - 1.33 Ghz Atom Z3735F, 2 GB RAM, 64 GB eMMC, Windows 8.1
2014 iPhone 6 Plus, 128 GB, Verizon, iOS 8.3
2013 iPad Air, 128 GB, T-Mobile, iOS 8.3