I'm not anti-Steam; I own dozens of games on Steam now. Well, rent them, really. And that leads to my attempt to present a balanced viewpoint.
People say you never actually own software; you're just renting it because of the effects of obsolescence and ephemeral software companies. But with Steam, that feeling of "renting it" is more pronounced. They own the files; you are just downloading a copy of it that sits on your hard drive
at their behest, subject to change or removal if Steam deems it must be.
Steam itself is continually being updated; it seems every other time I open up the Steam program, it needs to download an update before I can play my game.
The advantage of automatic game updates can be a double-edged sword in that sometimes you don't want an update or you wish to roll one back after it has been installed. To my knowledge, Steam does not allow you to prevent game updates or roll them back.
Steam does provide the capability of playing games offline in case you lose your internet but that provision doesn't seem to be ironclad. The very first sentence in an
article on this subject from a web site that I trust: "Steam’s offline mode is notoriously problematic."
If you are looking for that public beta discount and early access to the new version, you are not going to get it from Steam.
Lastly, even though it's not so much of a concern anymore, given their recent growth and success, OOTPD has a higher gross margin on games sold through their website and third party handler because Steam apparently takes a bigger cut of the proceeds.
Again, I happen to like Steam. I had to overcome these concerns over time in order to do so. Even so, if you present me with a choice between Steam and direct download, I am going to choose the latter.