Jonathan Seff over at Macworld made the journey from the full-size iPad to the new iPad Mini, and loves it.
In short, the switch from big iPad to little after three and half years has been relatively painless. In most ways, I’ve found the diminutive tablet more portable, easier to hold, and capable of handing what I want from an iPad.
Where Jonathan waited until the retina display came to the smaller form factor, I made the switch to the Mini a year earlier, when it first shipped, and I've now switched full time to the iPad Air. In many ways I agree with Jonathan, and his reasoning is impeccable: Same (or near enough) great display, same battery life, same processor, more portable. The trade-offs were much greater when I opted for the first-generation iPad Mini in 2012, but the portability still shone when compared to the weight and bulk of the iPad 3/4, and this certainly made my switch back to full-size more advantageous.
Nevertheless, given a straight choice between both new iPads I'm still coming down on the side of the Air: It's not significantly heavier than the Mini (at least it feels about the same in the bag I carry), it's a lot easier to hold all day than the old full-size iPads, the screen is a little bit nicer, and typing/reading/navigating UI is a whole bunch easier on the larger screen. That final one is, for me, the clincher—I'm faster and more productive in almost everything I use it for.
What's great of course is that anyone, like Jonathan, who finds the Mini to be more useful doesn't have to make any compromise in terms of performance. That's not a place I expected the iPad line to be by early 2014—let alone late 2013—and it demonstrates just how much of a leap Apple's made in terms of its own silicon over the last year. It's a great time to in the market for an iPad of whichever size suits you best.