It is probably a naive question, but why should someone install Snappy Ubuntu to a Raspberry Pi? I did not get the advantages over Raspbian Wheezy.
Maybe somebody has some experience or a case...
I have not used Snappy Core, but here's a few objective reasons:
Snappy Core is compiled for ARMv7, which means the software will better exploit the Pi 2's processor. Whether this makes that much of a difference I don't know; according to Diederik de Haas' comment below, Rasbpian's ARMv6 is almost the same as Debian's ARMv7 anyway (presuming that is the base of Snappy Core). I haven't seen any explicit benchmarks.
Ubuntu have a less conservative policy with regard to versions and updating than Debian. This means more recent versions of software will be available from their distro.
Snappy Core is set up to use a read-only filesystem. I do not think this is a great idea and it is a shame that this is what Ubuntu and the Foundation have decided to promote for the pi, especially since Ubuntu have more normal ARMv7 distributions that could be run on it. However, some people may appreciate and desire this.
I must admit to being totally confused by Ubuntu Snappy core.
I think it is meant to be an Internet of Things application. That is a minimal core system without desktop support. I don't think it is usable as a desktop system on the Raspberry Pi. I don't think there is currently even a working way to add further applications to the core system.
If you want to use Ubuntu on the Rapberry Pi I'd suggest you try https://wiki.ubuntu.com/ARM/RaspberryPi
If anyone can find an understandable explanation of Snappy core please let me know,
I think the best reason someone could install Snappy (in the Raspberry Pi, or any other arch) is the isolation that every Snappy package will have.
If you are trying to use your Raspberry Pi for a project that could handle deployable software components, then the Snappy packages (like Docker packages) are a really good way to maintain those components and their life-cycle.
In other words, every software you have installed as a Snappy (or Docker) Package (in difference with DEBs or RPMs) is that none of them, nor the OS share dependences. So you can have every library and software with their respective versions as your choice. If some package depends on a library A with version 1.x, and another package uses the same library, but version 1.y, then both packages can share the same system, run at the same time, and never interfere each other. And you can upgrade or maintain versions knowing that each one has their own "space". Their own "isolated sandbox".
You can try Docker in Debian if you want to have a similar "software life-cycle philosophy".
That's my opinion. I hope it is useful.
Snappy is console-based Ubuntu to test and run programs under Ubuntu (versus Debian, and both are different). If GUI is your need, go with Raspian.
Snappy Core is for developers at this point. I dont believe it is ready for everyday use yet. It appears to lack repos for downloading packages. If you want to tinker I'd go with Raspbian for now.