Each has its own advantage.
AW/Sager=HEavey as hell, run very hot, so hot my 7700 made it uncomfotrable to rest my left hand on the laptop (top of video card). However two optical drives and two hard drives are very nice. As well as the p4 chip in application use (3dsmax, etc).
XPS2= Lighter, runs cooler, hopefully better screen. Definatley more eye candy. From the pictures it the xps2 looks awesome. The 9860 is just very plain in my opinion, so plain it is ugly. Just a retangle 12.5lbs brick. My 7700 look alright, it added some flair to sagers/clevo plainess...
9860/7700 true DTR IMO(In My Opinion). XPS2 not so much unless you hang extra drives off the usb/firewire ports. I fear the centrino type chip might get worked over if you use some serious application (maya, 3dsmax etc).
This is why my strategy changed from replacing my desktop with the AW to keeping my desktop for doing 3d stuff (my side work I do from my day job hehheh). Getitng the XPS2 for a GOOD might change to awesome "LAPTOP" that I can carry with my easier on personal trips and play games sitting on the couch and at a friends house.
Great thing about the AW XL backpack I bought with my 7700 I can fit my xps2 ands my work laptop in it together! So when I travel I can have my baby and my work laptop with me. Yes their is enough room for both in that XL backpack.