Lightroom CC versus Lightroom 6
With the new version, Adobe gives users a choice. You can either go with the Creative Cloud release of Lightroom or stay with standalone Lightroom but still upgrade to Lightroom 6. In many ways, these are the same application, but there are differences.
First of all, let's acknowledge the obvious. Lightroom CC and Lightroom 6 are so similar it can be hard to tell which one you are using sometimes. Part of this difficulty stems from the fact that Adobe developed and released them from the same engineering team, and the two share so much code that it's not uncommon to encounter dialog boxes in each program that refers explicitly to the other one. This seeming split personality disorder has led many to believe that Lightroom 6 is the standalone version of Lightroom CC, and that Lightroom CC is merely the cloud licensed way of running Lightroom 6.
Upgrading from Lightroom 5.x to either the CC or Lightroom 6 applications installs a new version to your computer. Both are "upgrades" rather than merely "updates." This remains true regardless of whether you previously joined the Adobe "Photography Plan" that included Lightroom. Even if you thought you already had a cloud based version of Lightroom, you really still had the same thing as every other user of Lightroom 5.x had, even those who bought and installed a retail-boxed version. In the Creative Cloud world, incremental updates are patches to your installed application while "upgrades" give you a whole new installation that you can then migrate your catalog to. The new CC version of Lightroom is technically Lightroom CC (2015) and is thus an upgrade for all of us. I assume next year we'll see Lightroom CC (2016) just as I assume those of us running Photoshop CC (2014) will soon see Photoshop CC (2015). So switch from an older version of Lightroom to either new option is pretty much the same.
Once you get either Lightroom CC or Lightroom 6 installed, you'll find the same core program too. New features such as HDR merge, facial recognition and so forth are there in both. If you're used to the features found in previous versions of Lightroom, you'll find plenty of goodies in the new version regardless of what it calls itself.
But there are differences.
For one thing, Lightroom 6 is licensed for either OS X or Windows but not both. If you use both platforms you have to buy a copy for each. By contrast, Lightroom CC users who use both Windows and Mac can use their single CC license to install the application on a Windows desktop and a MacBook. You're limited to two activated copies regardless of which way you license Lightroom, but the two don't have to be the same operating system for cloud users. Lightroom CC also allows you to install a slimmed down version of Lightroom on your iPhone, iPad or Android device. The cloud version even lets you edit your native raw images on your mobile device and save them as DNG files for later optimization once you get back home. If you have the bandwidth and space, you can synchronize your photos between platforms too with CC but not with Lightroom 6.
Additionally, only Lightroom CC gives you access to the features found in Lightroom Web where you can have unlimited photo storage and photo sharing with feedback from other users. Note that users need an Adobe ID to comment so you're more likely to get feedback from other photographers than from family members who aren't photographers. This shouldn't be thought of as a replacement for more general purpose photo sharing sites like Flickr or Instagram.
The features found in Lightroom 6 will get bug fixes and you'll get support for new camera models if you license the standalone version. Additionally, you will probably see entirely new features added to Lightroom CC going forward. At least some of those new features won't show up in the boxed version until Lightroom 7, if Adobe makes such a thing down the road.
Adobe and its partners are trying to leverage the cloud in other ways too that will only work with the CC version. Already, Adobe Voice for creating animated videos and Photoshop Mix for combining and sharing images on your tablet or phone. Adobe is also opening up interfaces to allow third party vendors to provide services that integrate with the Creative Cloud universe. Only time will tell how this develops but standalone Lightroom 6 users won't have access.
Of course the obvious difference is that Lightroom 6 is offered as a perpetual license while Lightroom CC uses a subscription model. Buy Lightroom 6 and you're done. You can use it forever without paying Adobe another dime unless you want to upgrade in the future. License Lightroom CC and you'll have to keep paying or suffer the consequences. You can still access all your images and use the Library module no matter what, but you'll no longer be able to use the full capabilities of the Develop module. Adobe won't lock you out completely even if you stop paying completely, but your copy of Lightroom CC will only have limited capability without a paid subscription plan.
So what happens if you start with one new Lightroom option and decide later to switch to the other? The short answer is that you have to pay for the other one. If you pay for Lightroom 6 now and later decide to switch to the cloud, you won't get any additional credit to license Lightroom CC. Likewise, if you buy a subscription to Lightroom CC now and later decide that you'd really rather not keep paying for it every month you'd need buy Lightroom 6 to retain access to all the core features of the program. Keep in mind that converting to the standalone version will lose your access to the cloud-specific features only available in Lightroom CC.
If you download a trial version of Lightroom, it will function as Lightroom CC. If you later decide to buy the standalone Lightroom 6, your access to cloud features will go away once you enter the new license key.
And one final difference worth noting is that if you signed up for a Creative Cloud plan back when it came with access to Lightroom 5.x, you won't need to pay anything more to upgrade to Lightroom CC (2015) since it's included in your subscription. If you do want Lightroom 6 you'll need to pay for it whether you have a CC subscription or not.