iOS 9 marks the first iOS release where my thought has been a pretty consistent “Well, I guess Apple’s jumped the shark.” Most of the reviews I’ve read of iOS 9 have apparently been written by sycophantic Apple fanboys who don’t actually use their phones to do anything except take selfies and post to Facebook. I’m writing here from the perspective of someone who actually wants to use an iPhone as a tool. Sadly, things aren’t looking good.

In no particular order…

Low Battery Mode is a nice idea. It’s a single setting that does tweaks power things across the board when your battery is low. You can turn it on automatically (the low power dialog box now has an option to turn on low-power mode). Turning it back off later, however, requires navigating surprisingly deeply into Settings. The UI for the feature seems poorly thought-out. (Which, sadly, seems to be increasingly common in Apple products these days.)
The “return to last app” link is pretty convenient, but it’s uglier than I would have imagined possible in such a small UI element. The text has different size and baseline from the other text in the status bar, and it’s too close to the “back” arrow. If you have “Show button shapes” turned on (which I do), the underline merges into the letter. In short, it’s so ugly that every time I see it, I cringe involuntarily and think that somehow my phone must have glitched and displayed garbage on the screen. It’s a testimony to the aesthetic consistency (note: I didn’t say “beauty,” I said “consistency”) of the rest of the interface that such a minor element can look so atrocious because it violates so many design principles in so few pixels.
More bad UI (this is from iOS 8, but it’s still broken): Mail’s swipe actions still put “TRASH” on the same swipe gesture as “FLAG” or “MARK UNREAD” (depending on how you have configured your settings). This means the two most extreme, opposite options (“keep this and mark it important” and “delete this”) use the same gesture, differing only by a completely unpredictable combination of swipe distance and speed of swipe. This may go down in my book as one of the all-time worst UI decisions ever made in iOS, and iOS 9 doesn’t address it at all.
Greater battery life. I haven’t noticed, but as a big Apple fan since the original Macintosh, I have to say something positive, so I’ll pretend that the claim is true without verifying it. I think battery life has been extended, but it’s still not enough to give me a full day’s use.
The new app switcher interface is interesting in a vaguely positive way. In iOS 8, previously viewed apps were to the right in the task list. In iOS 9, they’re to the left, and they are full screen. I’m getting used to it, and it’s nice to be able to see the full screen view of what was happening in the app.
Spotlight sometimes fails to look up contacts. Spotlight on iOS used to search my contacts. I could swipe down, type the first few letters of someone’s name, and a tap would take me to their contact record. My business involves a lot of phone calling, and this was my #1 way to find a contact. From everything I’ve been able to determine, this randomly fails in iOS 9 about 20% of the time, and Spotlight doesn’t list matching contacts. So the only reliable way to look up a contact on iOS 9 has been to go into the Contacts app, scroll up, and type into the search box. And speaking of Spotlight and Siri… [Update: turning off Spotlight and turning it back on seemed to fix the problem about half an hour later. Maybe there was an indexing glitch or timing thing that made/makes my contacts vanish from Spotlight?]
“Smart” Siri guesses wrong, and recovering from her wrong guess is a lot of work. They’ve substituted “smart Siri” for the favorites” and “recents” that used to appear in the task switcher along the top. Since “smart” anything is almost guaranteed to give you the wrong answer 80% of the time, this is yet another big loss. My job is conducted on the phone, and “Favorites” an “Recents” were quite useful. Smart Siri only shows 4 choices, and it tries to figure out who I want to call, and it’s wrong.

If the theory is Siri should be “smart” to save me effort, then they need to consider what happens when Siri’s smarts turn out to be stupid. The failure mode of Siri guessing wrong is MUCH more work than “smart” Siri saves in the first place. I really would love a return to the iOS 8 model. (That’s why “favorites” exist! Because I know I want to contact those people often. Replacing my “favorites” with “smart” guesses is kinda weird.)

Maps now has transit direction! … not! Despite acquiring HopSpot, which does have transit directions, Apple didn’t bother including transit directions for much beyond San Francisco and New York. If you’re a pampered techie living in San Francisco, blissfully unaware that the rest of the country exist, I’m sure this looks like a big win. From the outside, it looks like a half-baked, duct-taped partial integration of functionality that’s already several years late coming to market. Apple has $203 billion in cash, and now we know why: because they sure as heck aren’t using any of it on software development.
Smarter web-enabled spotlight is ho-hum. I’m not sure who these people are who are continually going to new neighborhoods and cities and needing to know where the local eating spots are, but I pretty much know the neighborhoods where I spend 90% of my time. These relentless offers to show me ads from local businesses or help me find places to eat are ubiquitous and annoying, rather than useful.
Reminders now lets you move reminders between lists! Yay! But inexplicably, there’s still no way to delete completed reminders en masse. You have to swipe them one at a time. Since I have several hundred completed reminders, the swipe interface is not very useful.
Notes is better, but you can’t use the better-ness. As they did with iCloud in the Mavericks upgrade, Apple has implemented lots of new features in Notes in a way that is so incompatible with collaboration that it makes your head spin. In short, you can use all these great new features, but only if all your machines (including your desktops) are running iOS 9 and the next version of OS X (which isn’t out yet). If your notes are in a shared account with someone else, presumably they need to be upgraded too.

The problem with his scheme is that not everyone has the luxury of controlling the upgrade timing of all their devices. So it’s possible to end up with some devices upgraded and some not (or never, if the device in question can’t handle the new version of the OS), ruining sync ability without providing useful new functionality in its place.

This is not an impossible problem to solve, it just requires some thought and careful architecture. I’m sad that no one at Apple bothered to think this through.

Keyboard fail: they removed the double-tap-with-2-fingers-to-select-paragraph gesture. Since I used that very often, its removal has tanked my ability to compose and edit text quickly.
Ad blockers don’t work on iPhone 5. It says “not compatible with your device.”
Random major crashes. every now and then, with no warning, the phone simply freezes and requires a power-button-and-menu-button reboot to become responsive again.

On balance, the differences that I’ve noticed as a user, trying to get my work done, are mainly negative. The few positives are subtle enough that they don’t really do much to optimize my workflow. And removing the select-Paragraph gesture actively adds delays to any writing-oriented task I do on my iDevice.

Other than the features listed above, I’m having a hard time telling the difference between iOS 9 and its predecessors.

TL;DR

Underwhelming new features, and an explicit step backwards in many places.