Dell is a decent company but their machines are overpriced. If you were to pay $1000 on a Dell machine, you could probably get the same specifications in an ASUS or Sager for under $900 (this is hypothetical. Do not quote me on this). Also, some models of Dell laptop have been known to have heating issues and soft-touch button issues.
I would say that Sager is the best value for money and they have the best build quality. As I said, I am planning to get the Sager NP8130 and I have been searching for laptops for months and months on end.