I'm asking because I'm currently eyeing the Ubi Humble Bundle, and I haven't had any prior experience with Ubisoft's client before. At first I figured I would only get CoJ Gunslinger and Grow Home for a buck, but now I'm actually tempted by Far Cry 3, Blood Dragon and SC Blacklist as well; the last three require Uplay.

So how stable is their client? I heard not so great things about Uplay in the past, but I figure they had some time to fix things up a bit. How is it faring today?

Non existent for me.

It does its job. I've never had it crash on me and modern games seem to be patched automatically within the client as opposed to downloading patch installers, if you care about that sort of thing.

I can't talk about present day uplay, but in the past it used to run fine for me. The reason I didn't like it (and still don't) is that it's forced upon me and I don't give a damn about any of its features, aside from playing the games.

It boggles my mind that gamers still support Ubisoft by buying their crap. By far the worst publisher of all time that shits all over it's developing teams, destroys franchises, shits all over it's customers (have you guys forgotten StarForce? Always online with server connection? (SH3, Assassin's Creed), them releasing buggy, unfinished software and then dare to rip off it's customers with overpriced DLC?
Why do people still throw money at them?

Stability-wise, it's fine. I still dislike it, not on principle or for the client itself, but because each Ubisoft game I've played (and it's a short list, mostly HoMM and M&M) that uses UPlay also gives significant in-game benefits for playing while online, and won't let you use those benefits when offline. If that's not going to be a concern for you, then there's probably nothing at all to have a concern about.

I only used it about 3 years ago, and it was horrible then. The main thing back then was: disable cloud saves. It was made with always online as goal, and while by the time I played AC2 it was already patched out, it would still ignore local saves and just overwrite them with cloud ones. So basically, if you played offline for a while, next time you loaded it online all your offline progress would be lost. Cloud saves would sometimes fail to load even when online, so sometimes you would lose progress for no apparent reason. It was infuriating, and last I heard it hadn't been fixed because it was a "feature", so check around the options and disable them. Or maybe someone else will have more up to date info on the matter, but that's my big red flag.

Sounds like Uplay isn't all that bad then. I can live with that. I typically disable cloud saves anyway since they've never quite worked right for me, no matter what client I've been using. That and by the time i finish a game I'm unlikely to need those saves anymore. Because they've actually published some good games along the way? Just sayin'. Besides, the great thing about these Humble Bundles is that if I so choose I may decide not to give Ubi a single cent. ;) Then again, they'll probably use that as a tax write-off. *shrug* Eh.

Works great, never had any problems and i have many games there.

It's better than GOG Galaxy for sure.

I've tried plenty of other clients e.g Steam/Origin/Bnet as well. As it stands I rank Galaxy the worst among all (featureless and bloated updates), with Steam closely in second for being bloated/slow, but Steam client is superior than all in terms of functionality. Uplay and Origin are clean, fast and not resource hog but lacking many features Steam has.

Whether I dislike Ubi or not is irrelevant, I'm merely judging from Uplay quality as you asked.

Runs fine for me when I can be assed to run a game through it. At most of Ubis recent releases have been pure garbage I don't use it much except to run Watch_Dogs and even that is minimal. I have no other games I like to play on it. Have Ass Creed 3, but I put maybe 45 minutes into it?

It's not bad per se, there's just not really any games worth running on it.

They has some games that interest me a bit, like the anno serie or might and magic, and it looks they have a new south park game coming out (the first one was fun).

My only experience with uplay was trying anno 2070.
I liked it and then bought the retail box when the game just came out, when i tried to play it, the server was down and I was not able to play. The next day, it was still down and I was still unable to play.

Never tried uplay again, never bought for this plateform again.

While not a software engineer, my perception is that the client doesn't have issues, but some games that are exclusive to UPlay do, esp. those with auto cloud saving as someone mentioned.

When I played the HOMM 7(?) beta, that was pretty brutal, but zero issues with Valiant Hearts, Splinter Cell, or MMX or 1-6.

Uplay continues to maintain its status among clients the drooling idiot who wears a helmet indoors.