LR 5.7 works fine for me on Mac running Yosemite. You prefer LR CC? Isn't that LR6?
What are the benefits in comparisons?
Just don't feel like paying subscription to Adobe monthly for CC... I find that INSANELY ridiculous!
If you feel that way its probably not gonna worth it, but basically now there is HDR and Panorama inside the lightroom (Raw) which eats lots of ram.
also based on your configuration real-time performance is increased (GPU-based) solved a big pain of slow 1:1 panning for pixel peeping and sped up some sliders.
Creative Cloud is good in most aspects , having Photoshop and Lightroom for 10$ a month doesn't really sound that bad.
actually it opened doors for those who are interested but not going to use 'em professionally.