I recently upgraded my laptop to an Acer AN515. Here's some of my thoughts based on my purchase.

Don't get a small screen if you can help it. My 15" screen makes me squint. It also can't have all of the tools open in Serato. Sometimes Serato literally tells me that my screen is too small and won't display things. I do all of my practice and file setup on a larger secondary monitor at home, but screen isn't going on the road with me.

Make sure you get at least three to four hours of solid battery life. That's probably standard, but make sure it doesn't have crappy battery.

Consider quad core if you think you'll do some music production as well. Get at least 8G of RAM regardless.

Buy a new laptop. My 2012 Asus laptop was fairly top of the line when I bought it, but I found it was dropping beats during playback sometimes, which is why I upgraded. The faster it is, the more future proof it is.