For on-the-go compute I am using a 2017 12-inch Macbook (AS1534). This is a lesser known model, it was simply called "12 inch MacBook" (not air or pro) [0].

It has the aluminium body, it is ridiculously thin (3,5mm thinnest point, 13mm thickest point, feet included), it weighs just 920 gram. It charges via USB-C. It has a very good 2304 × 1440 (16∶10) IPS "retina" screen.

I run mine with MacOS/Linux dual boot, I charge it using my phone charger. It keep it in my go-bag at all times. I never have to worry being without it.

What to love:

- Super small, yet very sturdy.

- Can be found for relatively cheap (I paid €300 for mine 2 years ago)

- Really nice screen.

- Keyboard size is really good, though travel is obviously minimal with such a thin laptop.

- Plenty of battery life (and new batteries still available at Mac store last time I asked)

- upgraded model has 1.4Ghz dual core i5, 16GB RAM and 512GB SSD, which is still more than enough for on-the-go use.

What not to love:

- Has only 1 I/O port (USB-C), which is also used for charging.

- No longer receives MacOS updates, if you find a 2017 production model you get updates up to MacOS 13.

- Linux support is not great. The WiFi/Bluetooth chip (BCM15700A2) is not fully supported in Linux, WiFi works but Bluetooth doesn't. Audio via headphone jack works, but speakers don't. There are some experimental patches to get BT and speakers somewhat working, but it's not great.

If you can find it, get a late production model (2017) with the 1.4Ghz CPU upgrade, it will have 16gb RAM instead of 8gb (earlier models) and receive MacOS updates up to MacOS 13.

[0] https://en.wikipedia.org/wiki/12-inch_MacBook