I always have a dual boot system, so I left 32 bit Elementary on my main computer and installed the 64 bit version in the spare partition. Then everything went sideways. Too many 64 bit programs simply did not work in Elementary OS Freya and some wouldn't even install properly.
So I burned the most recent Mint 17 (17.3 at the time), but this time in 54 bit so I could use a few programs like Viber for Linux. And because I am used to the responsiveness of Elementary I installed Mint Mate. Bad move. Like stepping back in time. So boosted it to Cinnamon, which was also a horrible experience. Now, when I say horrible, I mean from 'MY' point of view. Thousands of people love those Mint flavours. But I like to tweak stuff and like the flexibility I used to have in KDE.
So I installed the KDE Plasma 4 package. And it picked up all my tweaks from the last time I had KDE running. All my 64 bit software worked as I installed it, and despite my earlier experiences, Mint KDE was mostly pretty smooth and snappy in its performance.
It wasn't all great though. There's a neat part of KDE desktop that few people use called Activities. I used them all the time. It allows me to not only have multiple desktops, but I can set each activity to be just like a separate computer and switch instantly between them.
So for example I used to have one Activity set specifically for Normal computer day to day stuff, another dedicated to Graphics, and a separate Activity for Video Editing. And each of my multiple desktops in the separate activities was uniquely designed to put everything where I wanted it.
But with Mint 17.3 KDE Activities were simply not available. A bit of Googling showed this has been a problem in other distros for some time, so it is not a Mint problem.
Installing a few packages as suggested in various forums gave me back my Activities, but killed my KDE. It took days to get the system more or less stable again and eventually I will have to reinstall and then reinstall all my programs and tweaks again.
But most of it is working again and working very, very nicely.
Mint 17.3 with KDE is slower to boot up than Elementary OS, but this latest version of Mint KDE seems just as fast, as long as you don;t try to get Activites working (assuming on yours it is not). And I now have my HD video wallpaper working more easily again. I had been so used to having to write special routines and script files to do things on Elementary that are just dead easy on other Linux distros.
Elementary OS is great for new users, but for long term Linux users there's just not enough flexibility for applying your own tweaks.