Here's the thing - for a modder/tweaker/DIYer/someone who's going to be upgrading components on a regular basis, Alienware is quite overrated. You can build your own - better - PC for cheaper, and it'll be more you .
However, I've learned that (shocker) not everyone can, or is interested in the modding/DIY/specwars game. They want something that just works when you plug it in, and its powerful enough to play some games or simply last them 10 Years. Perhaps they don't want to HAVE TO mod it, but want something that can be modded if they ever want to.
For these type of people, Alienware is actually quite good. It's not the best, and not necessarily the best bang for their buck, but the shopping experience is simple, is good stuff, and the chassis look badass.
That said I cannot recommend an Alienware laptop to anyone. They're shit.
What you're looking at, I see, it's a slim-tower Alienware desktop. This is not a chassis type that's not very common in gaming PCs or workstations. The case size also lets it work as a console replacement really easily.
Since there's not much else if this category, I have no problem with you getting this one, if you are in fact buying it because if it's slim-tower design.
Course, it all depends on you, and your use scenarios.