As far as quality of build, I think you be safe either way. And the OSes are similar as to not make much difference either. Other than the video difference, I think you need to decide how you plan to use the portability. The alienware system is really an alternative to a desktop system, as such it mainly designe to be transported then plugged. I think you'll find battery life an issue (not terrible, but noticable as compared to the mac). The power books are designed for the road warrior's mobile use, so it's lighter on battery consumption. Can't go by cpu Ghz ratings since the processor instruction sets are different. Whichever way you decide to go, dropped as much ram in it as you can afford and if you have a choice of video processors, go the workstion model over the gaming model. I envy your dilema.