A:AnswerIt is a one time buy, no subscription needed. The Lightroom CC is another option and is supposed to have a few more features. But can only be obtained through a subscription service. If you just want to pay once and have everything you will really need, just buy this! Program is amazing!
A:AnswerBecause Adobe will not be posting any updates to functionality of Lightroom 6. Already, subscription version of Lightroom is ahead of LR6 in terms of functionality. So if you are happy with what LR6 can do go ahead and buy it (I did) but if you think you would like to have app updated periodically you should go with subscription version.
A:AnswerAdobe Photoshop CC is an in cloud leased program. You do not own it. you are renting access. The Photoshop 6 program is the last licensed software Adobe produced that you own. Pre in-cloud. Once purchased it is yours.
A:AnswerOne tool I am aware of that is only in CC is the Dehaze tool. Useful if you shoot a lot of landscapes. Good news is you can get a freebie at prolostore.com that will help with dehaze in Lightroom 6