I am a satisfied Sentia owner. Not problems out of the box at all. I guess all the complaining is coming from couple of people who want to bash Alienware whenever they get a chance. Remember, you will probably hear from people who have problems, whether they caused it or not (i.e. adding memory, etc.), rather than the ones who are happy. Check the number of bash posts by the vocal few and you will see it is the same ones over and over and over and over (you get the point).
Also, check out Resellerratings.com and you will see that Alienware has one of the top ratings of ANY manufacturer. It isn't padding numbers over there, but rather people who give their rating and move on. Some of us don't have the time to keep a vendetta to make a point.
Hope this POV helps from the "few" happy AW owners.