It's mostly accurate, with a little whiff of bullshit. I wouldn't expect to be able to play on a laptop unless I had a pretty decent graphics card in there. Their minimum recommended GPU on the nvidia side is the GTX 560. Basically, if your laptop card isn't above it on
this list, you're not going to be doing so hot. I've got an 860M in mine, which benchmarks about half of the 560 (but is still pretty strong for most games), so my lappy won't be pushing this one. My friend, on the other hand, just got a laptop with a 780M in it, and that hits above the 560. But again, the 560 is their
minimum recommended. There isn't a laptop GPU that punches at their high level recommendation (GTX 780)
Can't speak to Alienware other than the always high prices. I can recommend the Lenovo, though. I've had a couple Lenovo Y models (the first died only after a couple serious falls onto cement). On the whole, I've found them solidly built and a pretty good power-to-price value. I have last year's model, similar to the one you'd be buying except for an i5 instead of an i7, and I can play most games on at least medium settings. As an example, I was able to run Arkham City on super high settings WITH Physx on at about 35-45 fps. Without Physx and at super high settings, I ran a clean 60fps.
One thing I've noticed is that games don't always pick up the nvidia gpu at first. You may want to check into your nvidia control panel to make sure everything is defaulting to reading the gpu and not the integrated crap.