The payout in an Apple upgrade

Apple takes a different approach with its OS X software for the Mac. It intends to offer a modest new version every year. Installation is a 15-minute, one-click operation, and the price is piddling. For OS X 10.8, Mountain Lion, which came out Wednesday, Apple wants $20 - and you can install one copy on as many Macs as you have, without having to type in serial numbers or deal with copy protection hurdles.

If you're a Mac owner, then, here's the question: Is Mountain Lion worth $20? (A note: I have written a how-to manual to Mountain Lion for an independent publisher; it was neither commissioned by nor written in cooperation with Apple.)

There's only one precise way to answer that, of course: assign a dollar value to each new feature.

Now, Apple claims "over 200 new features." But some of them are tiny tweaks (Safari checks for software updates every day! Ooh!) or techie-only treats ("Xsan, the high-performance cluster file system"). Fifteen are improvements for Chinese customers, which is great for Apple's world-domination plans but irrelevant to non-Chinese speakers.

So how many are real steps forward?

Mountain Lion continues to put velvet handcuffs on people who own iPhones, iPads and other Macs. For example, three iPhone/iPad apps are now on the Mac, too: Notes (a yellow pad, now with formatting and graphics), Reminders (a to-do list); and Game Center (lets you play against people on their Macs, iPhones and iPads, although few compatible games exist yet).

All of these sync with other Apple machines wirelessly, courtesy of Apple's free, increasingly sophisticated iCloud service. The new apps join Mail, Calendar (formerly called iCal) and Contacts (formerly Address Book), which already sync with your iGadgets. Change a phone number on your phone, and it's instantly updated on your tablet and computer; set up a reminder on your Mac, and your phone will chirp at the appointed time or even place.

It's all useful and a bit magical - if you own more than one Apple device. Clearly, the company wants to keep you a happy prisoner inside its beautiful walled garden.

So what's the value for these new syncing apps? Well, if phone apps cost $1 or $2, and computer shareware $20 or $30, then these new apps are probably worth about $7.

The new Notification Center is also modeled on an iPhone/iPad feature. It's a dark gray panel that slides onto the screen when you drag two fingers onto your trackpad (or click a menu-bar button). Here are all the nags, messages and alerts that your programs have issued, consolidated into one tidy, customizable list: today's appointments, incoming messages, software updates, Twitter updates and so on.

They tie into Mountain Lion's new alert system, in which each incoming alert bubble slides quietly into the corner of your screen. It's like a butler who tiptoes into your room with lunch, sees that you're busy, and sets the tray down on the side table before quietly withdrawing.

But being bombarded with bubbles would be a big bummer. So the Mail app's new V.I.P. feature lets you designate certain people whose messages you never want to miss - your spouse, your boss, the cable guy. You can set it up so that alert bubbles appear only when those people write. That's so smart. Notification Center: easily worth $3.50.

Dictation has come to the Mac, too. When you double-tap the Fn button on your keyboard, you can speak to type.

It's exactly the same recognition technology as the iPhone's. So it requires no voice training and no special microphone, but it requires an Internet connection. And the accuracy is not quite what you see in the Martin Scorsese Apple commercials for Siri. Still, dictation fast and useful, to the tune of $5.75.

The new Share button is a keeper, too. It pops up everywhere - in shortcut menus, window edges, programs like Safari and Preview, and so on.

Its pop-up menu lets you transmit whatever you're looking at: a photo, document, link, video, file. You can post something to Twitter, send it as an e-mail or text message, post a photo or video to Flickr or Vimeo, send a file wirelessly to another Mac and so on. All without having to open a special app or load a certain Web page. (In a free update this fall, Facebook will appear in the Share menu, too.)

This Share menu is a clever step-saver that you'll use often. It's easily worth $10.

Maybe the most routine-changing enhancement is Power Nap, a feature for Apple's latest hard-driveless laptops. It lets the laptop update Internet data even while it's closed and asleep.

Once an hour, it wakes itself - without activating any fans or lights - long enough to check for mail, download updates, run backups. When you wake the laptop later, you'll be delighted to find that it's completely up to date, with new e-mail waiting and all of your iCloud programs (Notes, Reminders, Calendar and so on) freshly synced.

Apple says that the battery hit is very slight. But if you're concerned, you can tell Power Nap not to kick in except when the laptop is plugged in. Awesome. Worth $11.

Messages, the former iChat chat program, has been enhanced to handle iMessages, which are basically Internet-borne text messages that cost you nothing. Whenever you converse with fellow iCloud members - whether they're on Macs, iPhones or iPads - the conversation appears simultaneously on all of your gadgets (and theirs). Start a chat on your phone when you're out and about, and you'll find its transcript in progress in Messages on your Mac. It's freaky, somewhat confusing, but worth $3.35.

AirPlay mirroring requires an Apple TV ($100), but lets you perform a real miracle: With one click, you can send whatever is on your Mac's screen - sound and picture - to your TV. Wirelessly.

AirPlay, already on iPhones and iPads, is even more useful on the Mac. You can send photo slide shows to the big screen. Or present lessons to a class. Or play online videos, including services like Hulu that aren't available on the Apple TV alone.

And for boardroom PowerPoint pitches, you can carry the tiny Apple TV instead of a $1,500 projector. A great feature, worth $12.87 - probably more to frequent PowerPointers.

Not everything is a step forward, however. Apple has tried to refine last-year's baffling AutoSave feature. It has restored the "Save As" and "Revert to Save" functions; alas, the result is almost more confusing than before. Worse, only a few programs incorporate this system - so you're stuck with having to learn two ways to save files. Subtract $3.25.

Apple's continued push to bring multitouch gestures from the iPad to the Mac's trackpad isn't wholly convincing, either. You swipe upward with three fingers to open the Mission Control app, spread four fingers to view the desktop, swipe sideways with four fingers to move between full-screen apps ... you're going to remember all this? I'm deducting $1.77 for that well-intentioned silliness.

Keep in mind, too, that Mountain Lion is available exclusively as a download. This time, Apple isn't even selling the software on a USB stick as a fallback. That's a big "tough rocks" to people who don't have high-speed Internet (yes, they still exist). Subtract $1.20.

Finally, I found the usual assortment of minor first-release bugs. Apple confirmed them and says they'll be exterminated shortly. That's a 35-cent penalty.

So by my highly scientific accounting, Mountain Lion costs $20 but nets $46.90 worth of enhancements. And that's not even counting the other 170 features: the Preview app (now lets you fill in checkboxes and blanks in PDF forms), Gatekeeper (blocks evil software), new screen saver slide shows, the unified address bar/search bar in Safari, the scroll bars that fatten up as your cursor approaches, and so on.

Over all, then, Mountain Lion is a gentle, thoughtful upgrade. All 200 new features? No, not really. But 10 that you'll use every day? For $20?

Yes.