Girlfriend bought Where's Waldo. I can't play it on the same computer she bought it on. I have no idea if this is by design or by defect.
Girlfriend boots up 360 while I'm playing RE5 on GFWL. Oops, signed out, because my tag was set to auto sign-in on 360. The reasoning behind this (prevent account sharers or frauds or whatever) is truly irrelevant to me. It negatively impacts me, so I don't like it.
Patching system is horrendous. With Steam, it auto-detects game patches and downloads them for me. With GFWL, I start the game, login with my gamertag. At this point it's probably been 30-45+ seconds. Oh, wait, game has a patch. Okay, let's patch it. Boom, game boots me out, and downloads and installs the patch. Okay, time to launch the game again. Oh wait, I have to sign in again.
But also, even if GFWL was exactly on par with Steam, why would I use it? I'm already running Steam 24/7. It has the same social functionality. It has achievements. If I wanted to "prevent Steam from gaining a monopoly", wouldn't I be rooting for the little guys, not Redmond, Washington?
And it's not on par. The selection is terrible, they don't have the truly epic sales the other guys have, they don't have any developer outreach in the indie community (with their only indie support being games that are on every other platforms). Efforts to improve the selection would mostly boil down to offering to sell me copies of games that I've already bought on other platforms, and efforts to secure better selection for the future will basically be the same.
Which is another thing. MS needs to stop being so schizophrenic with everything they do. Windows Phone 6.5. No, wait, Windows 7 but we'll still do 6.5. Here's the Kin! The Kin is cancelled! The Zune isn't cancelled but it's clearly not being supported. PC gaming is old, let's fire most of the GFW team, ignore the system for a year or more, and stop porting our games. Wait, now we like PC gaming, how come we don't have a foothold. The browser war is over, time to dismantle IE's team. Oh, no, now people don't use our outrageously shitty browser and developers hate us, I guess we'll set up the IE team again. Outside of MS's most very core products, their reliability for continued support is 0. I would trust some third-tier service like Greenhouse Games over GFW. The problem isn't that I doubt the sincerity of this change in direction, the problem is that I doubt there won't be another change in direction 12-18 months from now.
You say you want arguments for why GFW sucks besides "MS sucks, GFW sucks", but half the arguments for using GFW boil down to "It's Microsoft! And you can talk to your Microsoft friends! And use Microsoft achievements! How are those things better than anyone else's implementation? They're from Microsoft!"
When you say "Mindless rabble when get us nowhere", I disagree. Mindless rabble has worked spectacularly so far. I'm very happy with PC gaming. I'm very happy with Steam. I'm very happy that developers are increasingly abandoning GFWL. Mindless rabble has created an absolutely excellent situation right now. Ignoring the mindless rabble has gotten MS nowhere. Tough break, guys.