The extraordinary thing about Steam UI is how it's clearly just a browser .. but a very slow one. It's as if they've embedded a copy of IE6.
This seems like a problem with Valve's "No management, work on what you want to" [2] strategy. Maintaining (not to mention continually improving) a piece of software like the Steam client takes a lot of work, and it doesn't look like there aren't enough people at Valve doing it. There are new features like family sharing, big picture, and home streaming, but there's next to no progress on the slow bloated client that's constantly getting in my way.
I've bought a couple of things from GoG and I'll buy more as the catalog grows. I hope they eat Steam's lunch.
[1] http://forums.steampowered.com/forums/showthread.php?t=86186...