Yesterday's Steam client beta update introduced some minor tweaks to in-home streaming, a new library section for Big Picture mode and the ability to preload games to any folder rather than the Steam default. That last bit may not seem like a big deal, but it's one of those things that could prove awfully handy if you ever find yourself in need of it.
Let us say, for instance, that you have a PC of a certain vintage, and that your C: drive is a tad undersized—256GB, perhaps. You've dumped all your stuff on that drive over the years, including Steam, and as it started to fill up you added more storage, maybe a 2TB or 3TB drive, with more than enough space for everything. Life is good, except when you preload a game on Steam, because while you can install Steam games wherever you want, you can only preload them—that is, download new releases in advance of launch so when the clock strikes midnight, you can start playing immediately—to your default drive.
Given the size of some games these days— Watch Dogs requires 25GB of drive space—that can be a real problem if you're nursing your last 10GB on your primary drive, and utterly infuriating if you have hundreds of gigs of storage open elsewhere that you just can't use.
So yes, it is a pretty specific problem, but if it's a problem that affects you, this is a pretty big fix. The new update also addresses a problem with the in-game overlay sometimes not launching as it should, adds a library section for browsing and managing screenshots in Big Picture mode and tweaks up in-home streaming a bit with fixes including a workaround for a crash bug in the latest Nvidia driver release. You'll need to have Steam client beta participation enabled to take advantage of the latest update; to do so, simply launch Steam, go to your Settings and hit the "Change" button in the Beta Participation field, and then select "Steam Beta Participation."