In a few months my brother is going to get back into PC gaming and I am excited to share my Steam library with him. Does anybody here use the Steam Family Sharing feature, and if so, how well does it work?

It works well. Have a few people on it.
They can play any game until you start any game on your account. They'll get a message like you'll be kicked out in x minutes.

I've used it with myself, to play on my tablet a game that required my desktop's power. I traded the 3D rendering lag for some connexion lag, but it was still worth it. It is an amusing feature.

Just to clarify: are you saying only one person can play on the account at any particular time. Or is it that you can't play the same game at the same time?

If the former, I wonder if you can get around it by one person going into offline mode before the other starts playing.

As far as I know multiple people can play at the same time it's just that you the owner of the account can't play ANY game.

No, but I believe that only one game on one account can be played at any one time. This used to not be the case and there is one user here who has a chip on his shoulder with Valve (Or it's one reason why he doesn't like Steam anyway.) because of these changes. He will probably be able to explain how it works better than I can.

here's how Steam family sharing works. You login on their computer via whatever method and authorize it. They see your library sans 3rd party stuff that utilizes things like Uplay. They also see your DLC. HOWEVER, in the event you and another person share libraries, it can get finnicky if 2 people sharing have the same game but 1 has the season pass/DLC the other doesn't and give you access to the copy in the library of the one who doesn't have it. Steam may "register the game with the other shared account, meaning loss of DLC. If someone whose account you are sharing boots up a game in Steam and you are playing from their library, you have 5 minutes to shut it off. If you see the Division in shared library with someone,, ignore it-you can't play it due to the key being used.

Thats in home streaming not Family Sharing

That's me!

People have pretty much explained it.

Steam, unless you bypass the restrictions via offline mode or other means, will only let you play 1 game from a library at a time.

Have 100 games, play 1 and the other 99 are locked out.

VALVe, when they announced SFS, described it as a solution for families. That it would work like sharing books for DVD's.

The reality was far different.

VALVe refused to drop its 1 active game policy. Beta tester where very vocal over this, yet VALVe refused to enter into any dialog over this.

Regarding not used to being like this.... SFS has always worked like it.
There is a bug, a glitch, that lets some random people for some completely unknown reason Share games with out booting each other off.

STeam itself for the first 4 years did let your play multiple games at the same time.

Are you saying that if my brother boots up Civ III from my account, and then I start playing Borderlands also from my account, he will be booted out of Civ III?

Unless you are one of those lucky ones with this glitch, yes.

They will have 5 minutes to save and quit before being forced out of the game.

Just like sharing a book in real life. Five minutes after picking up an entirely different book, someone from Waterstones runs in and grabs the first book off your brother.

I should point out if the owners account is in offline mode, then 1 other person can play 1 of their games.

Borrower can't borrow in offline mode. This wasn't the case during early beta, which might be what
sherringon456 was on about. During early beta the borrower could go offline and bypass the restriction.

It took VALVe 6 months to add 3 lines of code to fix that. My paranoia says they did it on purpose, instead of complaining most people just used that loop hole. Valve closed it about 3 weeks before going live.

Looks like Galaxy is indeed a very faithful adoption of Valve's client. ;-P

Wrong, but some people are blessed with a glitch that allows that.

By default 1 game per library, owner will always get to play. 100 games, play 1 the other 99 are locked