Regarding the suspend/resume stuff, which version of Ubuntu are you running? I don't have a problem, but I had to do a couple of things to get it working more like a Macbook: http://karlgrz.com/dell-xps-15-ubuntu-tweaks/
This is almost exactly what I've done to set up my machine: http://ubuntuforums.org/showthread.php?t=2301071&p=13382949#... . This thread claimed that the kernel v4.3 fixed this issue, but it still happens for me - I was going to wait until the next 4.4 RC to give it another whirl.
If your BIOS supports it choose 'sleep' rather than 'hibernate' for suspend/resume. It will be a bit slower but there is far less OS dependent magic going on under the hood.