In 2.8, UI and Viewport are different with different gizmos, display options and workspaces properties.
Scene management is different with viewlayers and collections instead of sets of 20 layers visibility bits.
Grease pencil workflow has been tremendously changed.
Animation system is different with a different depsgraph and updated names in code.
It is not just render engine that is different. Every area of the software is different.
Some are slightly different, Some are a lot different.
Spring Team started its work in 2.79 and continued it in 2.8.
They are working in same building than developers. They had to wait green light from devs to make the jump and they are working with a new 2.8 build, everyday, updating their blend files while discovering issues with official devs ready to solve them.
That is a unique case and nobody should try to reproduce it because official devs can not be at disposal of everybody wanting to make an animation. They will thank you if you find a bug in 2.8. But that does not mean that they will solve the issue in priority for the day after.
2.8 is a work in progress and you can face a bug in every area of software that have been modified. That means anywhere.
2.79b has bugs, too, but they are known as non critical, with possible workarounds.
EEVEE is render engine of future. It means that is not the one of present. It is rendering movies or image sequences as animated textures, since yesterday. Before, it was not working at all.
It means that, maybe, bugreports related to that feature will come up in upcoming days.
EEVEE as Cycles is not rendering particles as Halos or Billboards. But point density texture is working with Cycles.
EEVEE does not have a dynamic Indirect Lighting.
It will not be able to render scene as heavy as the ones that Cycles can handle.
It does not do baking.
EEVEE may be sufficient if you don’t need that. But it is new engine and as the rest of 2.8, you may discover bugs by using it.
2.8 is a beta. And officially, you are using it at your own risk.