Re Intel vs AMD Intel is way better.
AMD is ok on the low end, and the integrated graphic chip is generally better than on Intel.
But for the processing power itself Intel processors are more powerful.
Depending on what you want to achieve a Core i5 may be enough.
But you may want to get a Core i7 with true hyperthreading to be on the safe side if you are a heavy plugin user.
Re XPS 15.
So far I am totally satisfied from a business / dev / graphics use point of views.
I haven't had time to do lots of X3.
You can have only one SSD but if you take the smaller battery you can have the 512GB mSata (Samsung btw) + a full size SSD/2.5 HD.
I don't think there are many notebooks with this size and thinness that allow this.
Regarding repairing there is no comparison with the new MacBook Pro which is in fact a serious downgrade to previous generation repairwise: it is way better.
I would like to see benchmarks usb 3 vs thunderbolt but I doubt there will be much difference with ssds.
I used to have esata and FireWire on my Dell M4400 workstaton but esata never really took of and improved, and I am so happy never to hear from FireWire again as there were always problems with chipsets/cards compatibilities.
If someone has monstruous projects that bring his pc/mac to its knees do not hesitate to send it to me for testing.
Additional information so far.
Really happy with this Ultrabook
Being more of a mouse guy I find the huge touchpad quite fine. Too bad it is a fingerprint magnet.
The screen is definitely outstanding. I have watched a few 4k videos from talented Jacob Schwarz, it is amazing. I calibrated it with i1, it is spot on 6500K and has huge luminosity of 365 cd/m2. Colors are very vibrant but there is a little metamerism: you may notice a slight hue change while changing the view angle.
I still think the huge resolution 3200x1800 is a marketing gimmick in most cases except for photography / graphic / design work but there are people who insist they can't go back to FullHD once they used retina or higher res displays even for office-type work. Indeed the text looks very sharp but one has to make do with old applications that aren't scaling aware and scale poorly (hello Photoshop CS6). Hopefully the situation will improve in time.
As habit would have it one of the first thing I did was to uninstall McAfee especially when I saw it happily using 600MB of RAM or more. True that's not a problem with 16GB but I never saw Windows Defender take that much.
The keyboard is very good for a chicklet keyboard. I did not like at all that the function keys had other uses by default (media keys, luminosity, wifi on and so forth) and that you had to press fn-Fx key to get the standard use. Thankfully I found that you could switch this behavior in Bios. The backlighting is very usefull.
For music production I'm always using the Quad-Capture. On the go though the xps15 speakers are suprisingly powerfull and decent. They come with Waves Maxx Audio 3 "enhancers" but I haven't played with the software so far.
Nuance Dragon Assistant (of Siri fame) is included with the notebook and I will test it this week.
So far I haven't used the touch screen that much, but it needs lots of firm pressure. It really isn't smooth the way a Microsoft Surface 2 tablet is, and I have limited success with a stylus. I'll have to investigate if the sensitivity can be configured.Update: there is indeed a configuration app in the control panel. Touch is fine now even with my capacitative stylus.
I am still in awe of the boot time. SSD + Windows 8.1 = win, and it sure feels highly optimized on the xps 15. Some of us may remember the 3+ minutes boot times of yore, I sure don't miss them.
So far I'm very satisfied, I'll keep in touch.