Well they are a bit like chalk and cheese, CoE is taking a unique look on the mmo genre and will be a truly rpg. I mean this as in you can do anything you want with no theme park limitations.
Ashes (AoC is Age of Conan) is the cookie cutter mmo with a few unique features.
I have backed both but my ashes is minimal because I believe it won't be unique and will have a short lifespan.
I am putting a lot of hope in CoE and even though it isn't exactly what I thought it was going to be i believe it will be so unique and will still hit alot of what I wanted in an mmo.
In regards production Ashes has some good looking videos but thats all they are. SBS on the other hand have shown us unique videos of gameplay and weather effects. We have also seen how voxel will work alongside the ue4 game and this shows that the team are working hard on the back end of the game and getting all the essentials in place. Plus imho the Dras look awesome and very much like their concept art. I am looking forward to seeing if the rest hit it. (They just need make the kypiq more evil looking....)
TLDR CoE is better than ashes