The new MacBook 2015 is not a MacBook Air or a MacBook Pro, it is 12-inch notebook, with retina display, it is even lighter than MacBook Air.
There are a few things you may need to know about the new MacBook:
1. Retina Display
12-inch retina display, with resolution 2304x1440. Is about 225 dpi.
The new MacBook has no fan. It is just 5 watt power, really low power, that's why it doesn't need a fan.
3. Only 1 Adapter Interface
There is only 1 adapter, USB-C for charging, input and output. So you can't plug in the external storage and charge the notebook together, but you can get an external adapter, just pay more.
The keyboard. Apple change the keyboard design from traditional scissor mechanism to butterfly mechanism. According to Apple, for older keyboard design, you need to hit the centre of the keyboard button, the new butterfly mechanism keyboard is more stable and more responsive.
5. The Apple Logo
The luminous Apple logo was replaced by a chromed Apple Logo. This is the least important, but this is not so “Apple-style” or “Job’s style".