Is using Mendeley to organize my files a good idea? My Library is already partially organized (manually) with regular filesystem folders. But it is pretty messy right now and getting unwieldy. 
Also several files should be renamed to something meaningful (right now paper titles-author-year is best for me).
I am wary of pulling the trigger, Mendeley may make things worse, not better. 

Any opinions? Experiences? Thanks.
I've personally used this feature, and I really like it - though honestly, part of the value I get from Mendeley is that I stop worrying about my files and folders and just use the software itself most of the time. As I have it sync them up I'm not even really concerned with where it stores them any more.

My recommendation is just to copy-paste your directory of files to a separate area "just in case", then fire away. File naming is (was) a pet peeve of mine, and I really like to have the files nicely named so I can search them - then I usually also sync that folder to Google Drive so I can access my documents anywhere (phone, guest account, etc).

It's a useful and nice feature, but honestly I found less value from it than I expected precisely as I began using Mendeley more. I still use the feature, but the other things the program does make it almost redundant - but still nice and I'm glad its there.