Wow, it looks great. xmonad got me hooked on tiling WMs but I had to switch to i3 because my haskell-fu sucked. At first it did not bother me and I was content with jgoerzen's default config plus a few minor tweaks. As I became more knowledgeable about xmonad it was obvious that my haskell handicap was preventing me from achieving the workflow that I wanted.
The one thing that worries me is the xrandr support borked[1] bug. Can anyone comment on xrandr and qtile?
It looks like if there is a problem, you can restart qtile and be OK. Also, you might be able to get away with setting your monitor configuration with xrandr before starting qtile.
If you like tiling and multiple monitor support, I suggest you check out Wingo. [1] It's a hybrid window manager written in Go, and configured in simple INI-like files.
Disclaimer: I'm the author.