It isnt?
All my old company used to use were Dell Laptops and desktops. A little over 600 of them in the building, we had switched over from Compaq. Having that many we saw some flaws in some machines. But it was just that, "some machines". They are computers, we only switched because we got a better deal when we were upgrading and the support that we needed was a bit better.
I wont buy a computer, I prefer to build it. That is just because I "know" what goes in it. Really though, I wouldnt sweat what brand if I were to buy a premade one, for me it is the best bang for the buck.