There is nothing wrong with having multiple desktops installed to a distro and switching among them.
Some persons will say you shouldn't have, for example, Gnome and KDE because it will install two sets of libraries and (gasp!) use hard drive space, but hard drives are so big these days that's really not a worry, not any more. If you are not using the libraries, they just sit there doing nothing; they don't get in the way.
Indeed, doing that allows you to use KDE programs under Gnome and vice versa.
On my Mint MATE machine, I normally use E17, but occasionally switch back to MATE from time to time.
Slackware comes with two desktops and four window managers out of the box. My Magiea install came with KDE and at least one other desktop, and I commonly use E17 on that.
Last edited by frankbell; 08-31-2014 at 08:37 PM.