I haven't given Ubuntu a proper try, except the one time I tried to make my plugins work with GIMP & Wine. Elementary looks interesting as well - their website mentions some of the Apple attention to design detail that I appreciate.
My suggestions: Xubuntu or Ubuntu w/o all the nasties, Elementary OS, Debian, Arch Linux or a BSD flavour.
So I install Ubuntu and am greeted by a broken screen, where 2/3 of the screen are on the right and 1/3 is on the left, like somebody cut a piece of film badly so it's the previous frame and the current frame together.
I asked around and apparently Ubuntu 16.10 doesn't do AMD anymore because AMD didn't write a proper GPU driver, and the old driver for Ubuntu 12.04 (that's from April 2012 haha) is broken totally for new hardware.
So here am I using Windows 7 Pro in a virtual machine on Windows 10 home which constantly bugs me with notifications, is very slow, eats battery and is generally horrible.
Meanwhile my MacBook Air (which only has 4GB of RAM because I bought it with my own money and I'm freelancing and am 16 years old) is laughing in the background...
So, no, Linux is not the solution... :/
Having said that, battery life on my laptops are terrible with linux out of the box.
If you do not like mac nor windows, maybe give Linux a shot? If you care about the mac UI you can make Linux look like it.
For software development and normal usage I do not feel like I am missing out on something by using Debian on the desktop and Ubuntu on my laptop.
If you use some specialised software for design you might want to check compatibility though