As convenient as Steam is, I'd much prefer the DRM-free copy, as the Steam Subscriber Agreement makes it quite clear you don't actually own
any of the games you pay full price for (even though Steam is littered with "purchase" buttons); you merely subscribe to/rent them. If at any time you don't agree to a change Steam makes to its Subscriber Agreement terms, they can summarily revoke access to all your games you paid full price for. Just like that.
Some relevant conditions from the agreement can be found below for those who care to read legalese. I'm in law school so I'm pretty used to it.
A. License Terms.
Steam and your Subscription(s) require the automatic download and installation of Software onto your computer. Valve hereby grants, and you accept, a limited, terminable, non-exclusive license and right to use the Software for your personal use in accordance with this Agreement, including the Subscription Terms. The Software is licensed, not sold. Your license confers no title or ownership in the Software. To make use of the Software, you must have a Steam Account and you may be required to be running the Steam client and maintaining a connection to the Internet.
9. AMENDMENTS TO THIS AGREEMENT
Valve may amend this Agreement (including any Subscription Terms or Rules of Use) at any time in its sole discretion. If Valve amends the Agreement, such amendment shall be effective thirty (30) days after your receiving notice of the amended Agreement, either via e-mail or as a notification within the Software. You can view the Agreement at any time at http://www.steampowered.com/
. Your failure to cancel your Account, or cease use of the Subscription(s) affected by the amendment, within thirty (30) days after receiving notification of the amendment, will constitute your acceptance of the amended terms. If you don't agree to the amendments or to any of the terms in this Agreement, your only remedy is to cancel your Account or to cease use of the affected Subscription(s)
. Valve shall not have any obligation to refund any fees that may have accrued to your Account before cancellation of your Account or cessation of use of any Subscription, nor shall Valve have any obligation to prorate any fees in such circumstances.
Fun consumer rights stuff. So I'd rather own my games outright than at the pleasure of the people I "purchase" them from. Hence why a DRM-free copy is always preferable, IMHO.