I bought a 1TB MyBook Essential drive several months ago for $100 at Staples and it has been almost flawless connected to my 211. It has fully enabled the DVR feature of the 211 and works completely as expected. (I detect some minor issues like crawl line "stutter" on some channels and an occasional complete momentary "shutdown" that corrects itself in a couple of seconds, but I have not confirmed they are due to having a drive connected or due to this particular drive.)
The only "real" issue I had was at activation when I called the 800 number that appears on the screen. What an episode! Call Tech Support instead.
Note that these cheap drives are not intended for 24/7 operation, so long-term reliability is TBD. I have to remind myself that most of the movies I record are not irreplaceable, but certain things like daily newscasts and sporting events are, so I need to be prepared for the eventuality of losing something I can't restore. I don't know if a "DVR certified" drive is any different from a reliability standpoint however, and for that matter ANY drive can fail at any time. Ask the 622/722 owners in these threads...!
