I use it.

Worth it? Depends on what you are expecting. I find it useful for keeping my installed games up-to-date, and as a launcher. But the main reason is: the more people actually use it, the more input the developers have to improve the thing. I could well live without it, but currently it is convenient enough.
If I had a slower internet connection or limited volume I would stay away from it, at least until compressed downloads and delta-updates are working.

no way

I use it.

It's mostly stable, but if you expect a seamless experience then no it's not at that stage yet. Feature wise it's still really lacking, right now it's good for keeping games updated and launching them but not much more. As toxicTom said, If you have a limited ISP you may want to wait for the next major update before jumping in as it should include compression/delta patching. Right now Galaxy is a bit of a bandwidth hog when updating or downloaded games.

Overall it's not to bad, but there are some bugs still... for instance some games still have issues not keeping time played, and when updates are disabled the notifications that an update is available can sometimes be weird. Importing more than one game at a time can cause issues.

EDIT: Be prepared to get a lot of biased views here from people who have actually never used it and go by word of mouth though...

I want to point out that I did use it. :D
Of course you are right but I want to make sure I'm in the clear here. :P

I used it initially but not recently. If GOG needs help testing something, I'm certainly willing to help out, but for now I don't keep enough games installed to have it really be of much use.

I do hope it's useful in getting more highly-desired games here.

PS: I don't play MP, so I can't say anything about the experience Galaxy provides here. But it could be another reason for some people to use it.

Like I've said before, I seriously want to give it a try and see how it goes, but there's no Linux version yet.

I do not use it. I used it to play TWAG, and don't use it anymore. I'll probably end up using it later.

I tried it since I was curious, but for me personally I just could not see a reason why I should use it, so after a while I stopped.

I use it. And whether its worth it or not depends on why you want it. If for some reason you want those unnecessary client launchers, GOG Galaxy fills that demand for GOG games. If you want an app to count the time spent in GOG games, GOG Galaxy is GOG's way of doing it.

But I guess you could say that its the frontend for multiplayer. You'll need it for some games that use it. Other features include having your GOG notifications delivered straight to your desktop; no need to go into the website in order to see your notifications. Useful for chatting with other familiars. The other feature that might matter to some is the auto-updating game, but if you do things manual, you'll be eligible to do rollbacks. I'm waiting for GalaxyTrail to wrap up the latest Freedom Planet beta to utilize this rollbacking feature, but I'm betting it'll be useful if something breaks in the new update and 'old update 4 life' stances.

However, if you come in expecting the useless-feature-a-thon a like Steam, its pretty barebones now, and that's just because its still a beta that is continually in development.

My final point is, if you are currently fine with the website, stick to it. If you really want auto updating and chat with friends on GOG a lot, or perhaps you just want to test it and provide feedback, get Galaxy.

It's so long overdue and still pretty much bare bones.

remember their BOOOOOM trailer about how GOG Galaxy is gonna rock the world?

Me neither.

Tried using it, stopped after a week (during the beta testing period where you had to clock the link to get an invitation(?)). Pointless. Gog should scrap that project and start working on the forum software, homepage hijinks (still getting bugs where i'm logged in but the header bar shows log in and register bs), getting their games patched up faster and providing us more linux versions of games.
Kids can get their achievements on steam if they like.

Also this: https://www.gog.com/forum/general/the_sorry_state_some_things_on_gog_are

I use it. As said before, it's mostly just handy for managing your games and that's about it. I like that I can basically access my GOG games with just a couple of clicks instead of having to open my games folders, but unless you're really into that there's no harm in waiting for greater progress.

Not using it. As a launcher its pretty pointless since I can start every game faster with dash (1-2 second fast app search) in Linux or Windows. The only thing that really interests me is for multiplayer for games like Ashes of the Singularity but that will have to wait for the time when the client comes out of its alfa state (another 2-3 years) and becomes usable.