Why are people assuming it's GFWL's fault for the savegame disappearing? This is not a common occurrence with GFWL games. Most likely, it's the game's fault. There's also reports of corrupt savegames on the 360 version, and it could very well be the exact same problem.
It isn't a coincidence that both are Microsoft systems, and I believe other games have had save issues like this one. I mean, it is clearly Rocksteady's fault for picking GFWL anyway, but GFWL has always done weird stuff with saves. If you change your gamertag, you lose your saves. Saves can be in random locations, cryptically concealed behind things that look like hex code.
I know GFWL uses its own client, but there's no signs of it being as big and slow as steam. If it's based on xbox live, it's most likely to be tiny as consoles tend to give extremely little resources to anything which isn't the game. I've got enough memory for steam, my annoyance with it is just how slow it feels in general and taking a large amount of memory is a good sign of it being bloated. To me, it feels pointless for it to be so big when I don't really utilize it for anything else but starting games. I'm sure other people don't mind it as much if it's their primary portal for games on PC and they utilize more of its features.
I just don't see the problem, though. Do you feel like it is slowing down your game? I mean, I hate when idle processes are running, too, but if I don't think they are affecting my performance, I'll stop caring.
GFWL, on the other hand has always been slower for me than Steam. Hell, Batman: AC, through its combination of GFWL and Securom takes upwards of 20 seconds from when I hit launch to when the game initially loads. Add in another 4 to 5 seconds to sign in to GFWL and we're talking about inconveniences significantly larger than anything Steam has ever done to me.