Dispay & Sound
The iPad Air 2 might give you more screen real estate, but the Mini 4 wins on pixel density, hands down. Like the Mini 3 before it, the newest generation squeezes 326 pixels into each linear inch of the device's 7.9-inch screen, making for crisp text and eye-popping visuals. Even better, Apple finally got rid of that tiny gap between the Mini's display panel and the slate of arsenic-free glass covering it; it's all been combined into a single, laminated panel.
What sounds like an exercise in LCD screen minutiae makes for some dramatic changes: It means less glare, better viewing angles and a touch more crispness. When we tested the Air 2 and the Mini 3, the difference in color clarity and saturation was pretty pronounced, but that's thankfully now a non-issue. Oh, and a brief aside: Older Minis also made a bit of a hollow thunk sound when you tapped them a certain way, an issue that's been addressed on the new model.
If you're hell-bent on using the Mini as a media machine, you've probably got a decent pair of headphones to go with it. Thankfully, you needn't fret if you accidentally leave them at home: The speakers housed on the Mini's bottom edge are impressively loud for their size. You won't be able to fill a room with the mid-heavy sound they churn out, but I discovered I could leave a video playing in the kitchen and still hear it while folding laundry downstairs.
Software
iOS 9 is such an important step forward that we just published a few thousand words all about it. Assuming you don't have the time to sift through our full review, here's a quick rundown on what iOS 9 means for the new Mini. In short, Apple's latest software update is focused more on stability and thoughtfulness, using Siri's new proactive smarts to surface information and apps when you might want them. Throw in plenty of neat design changes -- like a revamped app switcher and a fantastic "Back" button that lets you follow the breadcrumb trail of apps you were just using -- and we've got a more smartly put-together update than we initially gave Apple credit for.
iPads got plenty of attention in this update, and fans of mobile multitasking should be especially pleased. Consider Slide Over, which lets you swipe open a drawer full of first-party apps that can be opened in a smaller, separate window that takes up about a quarter of the screen. By jumping into any of those apps, you're effectively putting the other, primary application you were just using on pause until you're done texting or checking Apple News. You can go a step further and drag the line that divides those apps; that resizes both of them until they each take up 50 percent of the screen. Why hello, Split View. Honestly, as neat as this trick is, it feels sort of silly on a screen this small. Running two apps side by side makes sense on a larger display -- say, on a full-sized Air 2 or an enormous iPad Pro. Shoehorning two apps onto an 8-inch screen can feel a little claustrophobic after a while.
Then there's picture-in-picture mode, which, yes, is exactly what it sounds like. Any time you play a video in Apple's stock media player, you can tap an icon to shrink it down and stick it in a corner so you won't miss a moment of JK Simmons being an epic jerk in Whiplash. Give that small window a quick pinch-zoom and it'll roughly double in size; the default view on the Mini 4 is pretty tiny, so you'll probably spend most of your time in this mode.
Moving on, the Notes app also now supports richer text formatting (heck yeah, subheadings) and packs a reasonably thorough sketching tool for adding drawings and diagrams to your text. The smaller screens on iPhones make random doodling tricky, but that's not a problem with the Mini's nearly 8-inch screen. All told, iOS 9 is a must-have download, and the Mini 4 gives it plenty of space -- and power -- to shine.
