1. They often block legitimate users for no actual reason. Google for "steam account disabled for no reason" and see how many results it gives.
2. Their steam client is spying on your machine checking if you have any pirated games. In case it believes that there any such games, your account with ALL the games in it will be blocked FOREFER. Often they block innocent users despite they have proofs that they bought every game on steam, and never reply to their support tickets. They may block you only if you are saying something about piracy on their forums.
Proofs:
http://forums.tripwireinteractive.co...ad.php?t=42183
http://forums.steampowered.com/forum....php?t=1205792
http://forums.steampowered.com/forum....php?t=1126887 3. They will block you forever with all your games in case of a single problem with the payment, like paypal or credit card chargeback. NO REFUNDS. Proof:
http://www.slyck.com/forums/viewtopic.php?f=31&t=37355
4. They have paranoid antifraud system that blocks legitimate users from purchasing games while they are traveling (especially during holiday sale). Proof:
http://forums.steampowered.com/forum...&postcount=291
5. You are not an actual owner of the games you "bought" via steam. Agreement says: All title, ownership rights and intellectual property rights in and to the Software and any and all copies thereof are owned by Valve and/or its licensors. 6. They can take all games back whenever they want for any reason. According to Agreement: Valve has the right to terminate or cancel your Account or a particular Subscription at any time. And if it happens you will have to treat them with respect: "and remedy with respect to any dispute with Valve."
7. They leave you no choice. If you want to play games like MW2 or Black Ops you HAVE TO use Steam. Purchasing retail DVD makes things no different - you will not be able to play your game if your Steam account is blocked, even single player version. 8. They guarantee nothing, read chapter 9 of the Agreement.
9. Downloads are VERY slow, especially when new title is just out.
10. Support reply may take weeks, especially when many people have problems at once (like sales season or when new title is out) and there is absolutely no telephone you can call for support.
What remains? A large monopolist enterprise with totalitarian rules, that has right to block a user forever and take back without refund all games he bought before, and that uses this right very often to block innocent users with no visible reason.