Apple has pushed out the developer beta version of its upcoming desktop operating system dubbed macOS Sierra not long after it was unveiled during this year's WWDC.

For the uninitiated, Sierra is being built for MacBook, Mac Pro, iMac and Mac Mini. If you are asking why the new OS bears the moniker Sierra, Apple executive Craig Federighi provided a hint during its official introduction at WWDC 2016, saying the name is "obvious." It is likely because Sierra's headline feature is Siri (yes, Apple's personal assistant is making its way to the Mac).

Some experts are lucky enough to have the opportunity to get the first dibs of what is in store in the macOS Sierra.

Without further ado, let us have a rundown on what experts are saying about this recent desktop OS from Apple and let's check out a slew of its handy, new features.

Siri

For the very first time, Siri is heading to the Mac. One can activate it by clicking on the menu bar icon or on the dock icon. You can also trigger it by keying in Fn + Space. Unfortunately, you can't simply say "Hey Siri" to your computer for it to work.

According to experts who have tried this feature, this works very much like what many people expect. Through Siri, users can set reminders, ask for a particular email, make dinner reservations, ask for weather, send a text, ask for NBA scores, disable Wi-Fi, turn up the volume and a lot more.

However, it also has its downsides.

"[W]hen it magically finds that email you are looking for and you ask Siri to 'Open it,' Siri is at a loss for what to do," says The Verge. "Siri works better in a quiet room than a crowded coffee shop."

While Siri on Mac seems great and a big deal to most users, The Verge thinks that "it's much less important than some other features that Apple is introducing with macOS Sierra."

For Computerworld, in the meantime, the problem with Siri is that "it listens."

"All of my devices are set to listen, but when I have several around and ask Siri to do something, they all jump enthusiastically into action, merrily asking if I need their help," it says. "You can enable / disable Hey Siri on all the devices on an ad hoc basis, but that's cumbersome."

Multi-Tab Support

Another big feature Sierra brings with it is the multi-tab support to apps. With this functionality, users can launch multiple windows or open multiple tabs in apps like Pages, TextEdit, Maps or Mail (in addition to Safari, Terminal and Finder).

“There’s not much else to say, it works as expected,” says TechCrunch. “Tabs behave exactly like the tabs in Safari.”

Beefed-Up Photos App

Apple is also packing in a major update to the Photos App. This one incorporates Brilliance, a new editing tool, and Memories, a functionality that auto-compiles users’ photo stream into albums. What’s great with the latter feature is that it makes use of computer vision, geolocation and dates in putting together digital photo albums.

The Verge, though, says that these features seem a little buggy and slow, but considering that they are still in a beta stage, then there’s a big possibility that they will soon be fixed.

Picture-In-Picture Mode

Another notable feature Apple has added into this latest desktop OS version is the picture-in-picture mode. This feature allows users to pop out the video they are watching and put it in the corner of their screen so they can also browse the internet at the same time.

“Because I was testing an early version of the OS, most websites didn’t yet support this feature (an API is available to developers), but I was able to take an ESPN video and watch a recap of game seven of the NBA finals, all while opening and closing other apps and windows,” says Engadget.

What makes it even sweeter is that it is resizable.

Support For iOS Messages

Another good addition is the support for iOS Messages.

“In our hands-on testing with the developer build,” says CNET, “big emojis and invisible ink worked, while some of the other new text format features did not work yet.”

iCloud Desktop And Continuity

For The Verge, the combination of iCloud and Continuity features is the most important thing in the next version of Apple’s desktop OS.

With Sierra, iCloud can now sync users’ Desktop and Documents files. It also optimizes their storage by uploading old files into the cloud.

This means that users can access their files they are working on from any of their Apple devices.

Other Features To Arrive

A few other features for the OS are expected to land this coming fall, including:

– Apple Pay in Safari
– Feature that lets users unlock their Mac through their Apple Watch
– Universal Clipboard: this allows users to copy something, such as photos, files, contact information, etc., from their Mac and paste it on their iPhone

Bottom line: the macOS Sierra brings in a bevy of under-the-hood tweaks and marquee features which, according to Ars Technica, "refine but don't transform the Mac."