I've got to walk back some of the praise I was giving the controller the other night... the configurations for non-native Steam games are still a big mess. I started up Shadow Complex after a few sessions without problems and for some reason it had switched to keyboard+mouse mode, with the configuration I had made and saved totally gone. I had to start over with a new config, and after booting the game it wiped it out again and reverted to the default template. After making changes with the game running, nothing was saved and the default controls were still running. Then, after a few more attempts, it finally did store my changes, but they were once again wiped out and reverted as soon as I closed the game.
It's a pretty huge frustration when the customization tools for a controller sold almost entirely on the premise of customization fail. Hopefully they get this worked out soon... I know there have already been a few updates. I wonder why it's so problematic.
It's a lot better since the big Steam Beta update that just happened, but I'd still consider the Steam Controller itself a beta product because of the configuration tool. Always remember to export your configuration locally, at least.
I'm just glad Big Picture Mode is no longer required. >.<;