Ubuntu Snappy Core does not work on Raspberry Pi Zero, or for that matter on any ARMv6, such as most RPi models: 0,A,A+,B and B+. All of above are based on BCM2835/BCM2708 SoC.

UbuntuSC requires ARMv7 ISA CPU, which among Raspberry Pi models is only featured on the BCM2836/BCM2709 SoC in "Rasbperry Pi 2 Model B" (note the "2").

Also available:

DietPi http://dietpi.net/

Minibian https://minibianpi.wordpress.com/

Both Raspbian-based

And, in just 80MB, Slitaz-ARM http://arm.slitaz.org/

Though I don't know if the latter has SSH enabled by default.

Or Raspbian Lite: https://www.raspberrypi.org/downloads/raspbian/

This distro was just added a couple weeks ago, and is the same as Raspbian, but without all the GUI bits, apps like Minecraft and Wolfram, and it boots to the console without automatic login.

I used to use 'Diet Raspbian,' which took plain Raspbian and stripped it down, but this is a much nicer alternative, since it's an official build!

Or ArchLinux ARM: http://archlinuxarm.org/

Or Raspbian Jessie Lite: https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=1270...

Or better yet, build your own: http://git.yoctoproject.org/cgit/cgit.cgi/meta-raspberrypi

What do you consider "bloatware" - all the graphical X server and applications?

Precisely... for many use cases you don't need them. It's better if you start with a server distro.

I tried Snappy and won't use it again. to enable wifi involves manually installing dpkgs, rather than using the snappy package system. that's a regression from ubuntu.

Good tip. Also, there are options that can be built from source (e.g., BSD) so that all that cruft is not installed by default. IME, 8 GB SD cards are not needed; 1 GB and smaller can suffice.

Ubuntu only works on Raspberry Pi 2.