MATE would be my go-to alternative today, but in the future this may change. Looking at a few years down the road, I'm excited about the prospect of the LXQt desktop environment. In its current state, LXQt brings us the lightweight/modular goodness of LXDE, bundled with Qt-centric controls to make manipulating the desktop experience as simple as possible. Right now, this is an area LXDE is lacking and I believe the Qt component of LXQt could be a nice fix for this problem.
With regard to recommended applications, it's important to remember this desktop environment is still very much a beta project. So when it comes to desktop applications, you could always look to this Razor-qt specific wiki for application suggestions. As a general rule, you might be inclined to use the Qt based software where applicable.
Also, I need to touch on something important. GNOME, KDE and Cinnamon remain solid options for anyone looking for a good desktop Linux experience. All three desktop environments provide tremendous flow and an amazing smoothness when navigating through the desktop space.
The reason I don't recommend any of them as an XFCE alternative is that they simply don't match up to the end user experience. XFCE is lightweight and provides a minimal GUI that provides an easy-to-use desktop without a ton of configuration. For now, sticking with XFCE is still very doable for most folks. However, as things with GTK3 continue to roll out, it's entirely possible we'll see XFCE becoming incompatible to a point where a switch to a new desktop becomes a must.