@timpster the reason the applet is called xfapplet is because mint menu is not an xfce applet, it's a MATE applet. In the Gnome 2 era, xfapplet allowed the use of some Gnome 2 applets, including the mint menu, on xfce. After Mint stopped supporting Gnome 2, Mint Menu was ported to MATE and was no longer compatible with xfapplet. Mint has now added MATE applet support to xfapplet. Basically, you add xfapplet to the panel, which then gives you a list of MATE applets that you have installed that work with xfapplet. You only have the mint menu installed, so it only lists mint menu. However, if you were to have other MATE applets installed, it would show them in the list too. I don't know how easy it would be to add the mint menu through xfapplet to the xfce applet list.
I think that right now the xfce version has two purposes. The first is the purpose of xfce in general - to be a fairly functional lightweight alternative to bigger desktops. The second is specific to the Mint Xfce edition, which is to include most of the software you would normally expect, so it trades speed for more functionality. The xfce menu is functional and light, so it would go with the first purpose, whereas the mintmenu fits with the second purpose. If there was still a light LXDE version of mint, I'd say include the mintMenu, but the Xfce edition has sort of inherited the purpose of the LXDE version. In the end, I say xfce menu because people usually come to xfce after kde/cinnamon/MATE were too slow for them. However, I am happy with either - I use the mint menu on Xfce, so I'm indifferent.
mintmenu is not defaults
today I put in virtulbox edition xfce and xfce menu is the default
mintmenu is installed as applet
Mint menu is already in that edition http://www.linuxmint.com/rel_maya_xfce_whatsnew.php