When I used LXDE, it had a long way to go before it could be considered equivalent to Xfce, and I ended up switching back. The ultra-lightweight window managers may be in fashion, but Xfce is mature and polished and easy enough for my mother to use, and I can't say that about Lubuntu.
The typical Ubuntu user probably won't miss much on Xubuntu. When they find that mrxvt doesn't let them use Ctrl-C/V to copy and paste, they'll be mystified. Ditto for Openbox's wu wei panel management.
I had a similar experience. Xfce could handle my differently-sized dual-monitor setup easily. LXDE failed such that it thought to put some things off-screen where I could never reach them.
I use tint2 as a "panel" of sorts in Openbox, and modify menu.xml for anything else I need. I like it well enough. Also, modifying rc.xml allows one to set hotkeys.
sudo apt-get install xubuntu-desktop