Replaced my 13 with 15 RC a few days ago. The new file manager is pretty nice. Right click to run with higher privileges pops open a new file browser window with a big red bar letting you know so you don't walk away and end up screwing something up when you get back. Also shows a small bar graph under each mounted partition so you can get a good idea how much space you have left at a glance. "Disk Utility" is replaced/merged with "Storage Device Manager" so I can just go to one place for all my partition renaming, automounting, and SMART options now, which seems to have gotten rid of a glitch that would always try to read my first two drives (sda, sdb) as identical drives for some reason. As of yesterday I still had a glitch with automounting my old Mint 13 partition at bootup but it mounts fine if I instead click on it in the file manager after booting. Mounts all the NTFS partitions with no problems. New applets organization makes it much easier to install applets without futzing with the terminal (This is important for newbies and out of the box experience.) but getting some of them to actually WORK after installation is another story. Having issues with the weather applet at the moment. In previous versions I also had issues with my firefox tabs locking up randomly, seemingly caused by a new song coming on the media player and the popup going over the tab button. Minimizing/maximizing the browser made it return to normal for a while. This glitch seems to have been fixed as well. Backed up and recopied one of my VM's to the new OS and it seemed to have spasms and refuse to shut the VM down but after a few cycles of update, force close, install guest additions, force close, startup again it went back to working order.