Excerpted from the ones I've seen. More as they come in.
Dan Ackerman, CNET: The iPhone 12 Mini may be the most interesting of the bunch. Back at the dawn of the mobile phone era (circa Dotcom 1.0), the real status symbol was having the smallest phone possible. People would go to lunch and casually place their phones on the table in front of them, and the tiniest phone was the unofficial winner. The iPhone 12 Mini feels like a return to the idea of packing the most features into the smallest body. While it's not as flashy, there's a real hunger out there for premium phones in smaller sizes, and I hear all the time from people how the latest super-premium smartphone is "just too big." With a 5.4-inch screen and the same features as the regular iPhone 12, this 4.8-ounce phone could be just right for anyone with small hands or small pockets, or who just wants something less tablet-like. In my average-size hands, it felt incredibly small, which really just shows you how much we've been acclimated to huge phones.
Chaim Gartenberg, The Verge: Sizing up the iPhone 12 mini. [T]hat smaller size is really nice to hold. iOS scales well to the 5.4-inch display, and the iPhone 12 design looks and feels just as nice on the slightly more compact version as it does on the full-sized model. If you liked the size of the the old 5 / 5S / SE, though, the 12 mini feels like the closest Apple has come to that style of device in a long time. It’s honestly a bit weird to hold at first, especially if you’re coming from a big phone. Some things do take a bit of an adjustment, like typing — but other parts of using an iPhone, like swiping down from the top of the display for notifications or the control center, are easier than they’ve been in years. But for the first time since arguably the iPhone 8, Apple has made a flagship phone that nearly anyone should be able to comfortably use and hold in one hand. There are some concerns: the smaller physical size means that the mini has a smaller battery, which could translate to lower battery life, too — especially with 5G in the mix. We’ll have more on that, along with a much more comprehensive look at the 12 mini, once we’ve done a full review.
My take: Frustrating to have only these quick, hands-on reviews.