My personal issues with Steam are mostly minor annoyances, rather than show-stopping problems which would force me to remove it from my system forever.

One, the client has a bad tendency to suck up a bunch of memory (>100MB) whenever it feels like it, and not release it until reboot.
Two, though it does let you install games on any drive, you still have to install them into its own managed directory structure. I have the vast majority of my games installed on, say "D:\Games", and I can easily browse that directory to find any game I have installed, EXCEPT for Steam games. They are ALWAYS nested several subdirs inside whatever "Library" folder you tell Steam it can use on that drive.
Three, I have turned off auto-updating on Steam and all the games in the past, and it STILL has randomly started up doing some kind of maintenance in the background, interfering with what I am doing at the time to the point where I have to shut it down completely to get it to stop.
Four, the client has developed a recent tendency to fail to connect to the Steam servers upon boot, and I have to tell it to retry every bootup/restart. Of course, for some reason, it also thinks I want to view the store window when I do that, so I have to close that down, too. "Retry connection" does NOT mean "take me to the Store!".

Outside of those and a few others not worth enumerating here, it works OK. I don't have any plans to publish games through an aggregation service like Steam; we're just going to stick with self-publishing.