Although that is a good price for an Alienware unit, the HP ENVY H8-1420t base model seems to have a bit more going for it. Another option, a boutique builder such as CyberPowerPC has at this time the Mega Special II for just a bit more (once the OS is added) but can be customized down to the Alienware specs for a bit less
There are other options but those two feature i7 processors and for about the same price as the Alienware, the HP can be equipped with the same GPU (the stock one is a little lame).
The CyberPowerPC build there is a bit more than the Alienware once OS is added, unless you use the same processor as the Alienware, in which case it's less expensive. But they also give you an unlocked CPU as the base and a better graphics card along with a 2TB HDD which, in my eyes makes it a much more potent machine and, should you decide to get a performance boost later, you'll be able to overclock.
What are the most CPU intensive tasks you do with your computer? What games do you play and what are your monitor's specs? This information should help me guide you to the best option