As the title says. I have a feeling it's still missing way too many features to try to build a project on top of him. What do you think?

Considering there is not a beta yet Id say no

No and to be honest unless you are about to build a mamoth back end feature and don't want to have to redo it in the next 2 1/2 years i wouldn't go to 14 when the beta or rc are out. I would stick with the long term support and well tested v13 until you are sure.