I have a Dell XPS 15 L501x. Was considering the XPS 15z. Need some opinions.

Currently I have the XPS 15 L501x. It has the i5 m460, 6GB DDR3, 640GB HDD, GT420 w/ optimus, 1080P screen (awesomeness) and a 9 cell battery. Originally I had purchased this for school and some gaming (MW2, etc..) Turns out I dont game at all on notebooks because thats what I have my gaming desktop for, and I just graduated so I wont be using it for school anymore. Only thing I use it for now is web browsing, netflix and watching movies when im on a plane for vacation. It does everything I want and then some.
I wanted to maybe sell this laptop and get the XPS 15z. Reasons because its lighter and thinner. I frequent this forum alot and I've read all the comparisons between the XPS 15 and XPS 15z.
Questions would be:
How are the speakers on the 15z over the 15? I like the loudness, I dont really need the subwoofer so i'm okay with that.
How about the screen? From what I read I understand that the 1080p screen on the 15z is not as good as the XPS 15, but is it that much worse? (I use my laptop now for netflix and blu-ray rips)
Battery life? Currently with my notebook and battery mode and backlight down, I get 6 hours of battery life which is great for flights, how is the 15z
And finally, is it worth it to even change? I got this notebook for a great deal ($600 even) if I were to sell it, what would be a good asking price for it? (Its still under warranty)

I love the build quality on the L501x and from what I read the 15z is built nice and sturdy as well. Only thing im missing is the backlight keyboard which I can always add but I'm good without. Just wanted opinions from people who have/had both. Thanks

 

over 50 views, no1 got an opinion? lol

 

I am in the same boat as you; however, after reviewing some differences that matter greatly to me, I'm inclined to stay with my L501x. The main reasons are the better screen, speakers, and webcam. The B+RGLED is unparalled compared to all the screens that I have seen in my life. The 15z has worst color gamut, viewing angles, and contrast. Now this may not matter to some people, but for me I can't use any other screen after being "spoiled" by the B+RGLED. Sound is also extremely important as I travel quite a bit to my gf's school so watching movies is a charm with the JBL speakers with subwoofer. And finally since I skype often, the 2.0mp webcam has also spoiled me. I realize that not everyone is sensitive to these higher quality specs, but I have found that it matters alot to me so therefore I will stay with what I have unless the components are upgraded on the 15z.