Later this year, Apple will release OS X 10.10 Yosemite, the latest version of its Mac desktop operating system. It will run on all the same Mac models as OS X 10.9 Mavericks, and will be a free download and update.

That's all expected, but there are some unexpected changes coming with Yosemite. For a start, Apple is offering a public beta of the operating system, something Apple hasn't done since it was preparing to launch OS X in 2000.

Anyone can apply, but bear in mind this release is for testing bugs, not a demo of the finished OS. If you apply and are successful, make sure you follow Apple's advice on backing up and installing somewhere safe carefully.

I've been trying a beta build provided by Apple, though, and have had a chance to dig into the more important changes for most users: the extra features. Unfortunately, because I've only been able to preview Yosemite alone, and not iOS 8 or the new features of iCloud, I actually can't give my opinion on some of Yosemite's best features: Continuity and the new iCloud options.

Yosemite offers the ability to pass tasks between it and iOS (known as Handoff), and to take phone calls on your Mac, send SMS texts from your Mac, and set up your iPhone as a mobile hotspot instantly from your Mac. iCloud Drive, meanwhile, gives you a very smart way to get data between iOS and Macs without having to put any effort in. These are easily Yosemite's most exciting possibilities, so it's a shame I can't talk about them.

Design

That's not to say there wasn't a lot to dig into. The biggest and most obvious change to Yosemite is the design, of course. Taking a leaf from iOS 7's slightly transparent book, windows are simpler, and some have a see-through element, revealing soft hints of the windows beneath them.

It was a contentious look in iOS, but I'll stick my neck out and say that it really works in Yosemite. The change hasn't been as dramatic as the iOS switch was, with OS X retaining more of its earlier style, and having already made small steps towards slightly simple, 'flatter' design in aspects of Mavericks.

OS X 10.10 Yosemite review

It's more colorful in some spots, less colorful in others, but pretty much always striking – at least, coming from using Mac OS X 10.9 or Windows 8 day-to-day. The new Helvetica font looks great on Retina screens, and the brighter, simpler icons match the starker window designs nicely.

On non-Retina, though, it doesn't sing quite as strongly. Small text can be hard to read, especially in areas such as the progress bar when copying files. Here the text is presented as mid-grey lettering on a light-grey background, which just isn't that legible.

Text layered on transparent background or over images can also be more difficult to read. There's simply less definition to the text, so in a busy setting, it can sometimes get lost a little.

The new font loses a bit of elegance in its more jagged form, too. It's not hard to read, but it has definitely been designed with Retina in mind. Nothing here is so bad to be a show-stopper by any means, but there's no denying that OS X 10.10 is much more at home on Retina than not.

The Dark Mode is a nice touch in theory, turning some white elements of the OS dark black to make thing easier on the eyes in lower light level, but it's kind of only half a feature. It makes the Menu bar and Dock darker, but that's it – all the shiny light grey and white windows are still bright.

OS X 10.10 Yosemite review
Dark Mode will be fantastic for burning the midnight oil

The simplification aspect of Yosemite isn't about stripping away options so much as just putting them somewhere a little tidier. In some cases this means putting buttons that used to sit just below the title bar higher up, so less space is used for window chrome and more for whatever you're doing in the apps themselves.

At least, that's the idea. In some apps, it's been included well (such as Safari and Maps), but it's not consistent. For many apps, including Mail and Preview, the icons sit below the title as they always have.

This occasional change goes hand-in-hand with the new translucent elements. Again, they're not present in every app, and when they are it is sometimes surprising. Safari and Maps have translucent titles bars, enabling you to get a glimpse of the content within those apps that's 'hidden' underneath the interface.

But Messages is different. It's half translucent (the list of people on the left) and half solid (the actual message on the right) – a division that stretches all the way through the title bar, leaving a strange half 'frosted glass'-half solid effect

OS X 10.10 Yosemite review
Meet the new Mail, (pretty much) same as the old Mail

Then you have Mail, which has a solid title bar and a Messages-like split view below, except both the list of emails on the right and the message itself are solid white. If you bring up the Mailbox list to view your email folders that is translucent, but that translucency doesn't extend up into the title bar, as it does with Messages.

Popup windows are usually translucent (things like Share windows or details of a location in the Maps app, for example), but at the moment, I'm not sure this new element of Yosemite is as consistent as it could be.

OS X 10.10 Yosemite review
Apple's hot on Continuity, but what about consistency?

Another thing that can trip you up is that Apple has moved the 'fullscreen' button from the right-hand corner of a window to the green button on the top-left, which used to have the slightly nebulous function of fitting the window to the content. That functionality is still there if you hold alt and roll over the green button, though.

However, not all apps support full screen, including Apple's own apps, which means that sometimes the green button is a plus sign, indicating it's the old behavior, and sometimes it's two arrows, indicating it can go full screen. Having two behaviors from one button color means you won't know what it does until you roll the mouse over it to see the icon, which seems a little odd.

Apple has definitely given OS X 10.10 a striking new look, and I really like it, but I wonder if the company might yet do a bit more tinkering with the interface in different apps before release. The inconsistency doesn't affect usability; the apps all work largely how they do in Mavericks, but when sitting down to explore Apple's new direction, it left me scratching my head in a few spots.