Well, Lightroom 2015 CC is the better option.
What extra you get is the Lightroom Mobile & Web for Editing you images on the go
Dehaze is only available with Lightroom CC 2015 not with Lightroom 5
More Camera Support with Lightroom CC.
As a point of clarification, Lightroom CC is the creative cloud version of Lightroom that you download and install on your computer, but you pay $9.99/month to use it. For that monthly fee you are also entitled to the latest version of Photoshop. There is another version that has most of the features of Lightroom CC, Lightroom 6. It is the current standalone version of Lightroom. If you have a previous version you can upgrade to Lightroom 6 for $79.99. If this is a first-time purchase of Lightroom then the price is $149.99.
Lightroom 6 does not receive feature updates like Lightroom CC does. Lightroom CC has a dehaze adjustment, and a few other features that have been released since Lightroom 6 was introduced. I suspect Lightroom standalone version will eventually get those features, but it will be another paid upgrade for you to get it. Personally, I think the subscription plan is an excellent value. You don't have to wait for new features, you have both Lightroom and Photoshop, and you also have Lightroom Mobile that you can use on your mobile devices. A lot of users are skeptical of the creative cloud plan and choosing Lightroom 6. The programs are fundamentally the same except for the new features that have been added. Either version is an improvement over Lightroom 5, in my opinion
whats best... Lightroom 5 or lightroom CC
Care to define what you mean by "best", Stephen?