if you would like to stick with the price, i would prefer asus. otherwise, i prefer this:
as for me, i would wait for dell to low down the price of this and then get it...
below is the image that i did in the past to compare this dell xps laptop with macbook pro (note: there is a discrepancy in this comparison that you would be found in support. it should be one year for both... copy cell problem...):
I was looking at the XPS 15 just a few days ago. I find it to be quite an intriguing product. Never been a huge dell fan, but I am very excited that someone is making a retina-level LED display for a laptop, and a Windows 8.1 convertible laptop at that. If I had to choose a laptop right now, it would be the XPS 15 without question. I ended up repairing my old Sony Vaio 18.4" laptop (which only has a 1920x1080 screen of TERRIBLE quality) for only a couple hundred bucks (because that's all I have at the moment)...but the XPS 15 is definitely on my radar.
BTW, onboard memory sounds like memory that has actually been soldered onto the motherboard. That isn't surprising, given how tightly Apple engineers their products to meet extremely tight specifications. I suspect Dell is using a standard form of laptop memory, which would be much more versatile.