So I've been using XFCE at work and at home for over a week. I tweaked and fiddled and got it working close to how I liked. It's not bad. I think I prefer the terminal program they supply - xfce4-terminal.
Today I switched back to FVWM.
There were lots of little reasons why I moved back. Lots of small irritations that built up until I wanted to go back to a cleaner faster approach.
There's too much screen real estate chewed up with non-essential things. Left edge, right edge, bottom edge, icons on the screen. I like a clean empty desktop so I can make windows as large as possible.
If I had a large terminal window and moved it, it redrew itself insanely during the move, which made the move so slow. FVM freezes the window, moves quickly, then unfreezes. More sensible.
XFCE looks nice, really nice, but it's a little slow. Not as slow as KDE, but slow enough to be irritating.
The pager moves up and down. Right above it is the list of open programs on that desktop. If you switch to a desktop with 10 xterms running, the pager moves halfway down the screen. Irritating. I want things in one fixed place, so my eyes can flick quickly there to see the situation.
It's really hard to change the menu system. In fvwm, I have a totally custom menu. All my stuff is on top level of menu for fast access. It's a real struggle to make changes to the XFCE menu, and occasionally it reverts back to the default menu.
So all in all, lots of little things finally pushed me back to fvwm. I'll use the xfce4-terminal more now, and Thunar (the file manager) and I'm happy I made the experiment, but I'm happy to be back in fvwm where things have been the same for 16 years and hopefully will be the same in another 16 years.