I chose dwarves because I generally prefer dwarves to elves in any story.
Also, I understand they tried to make the elves more war-like instead of fearies, but they look like they have risen from the dead. And they really don't appeal to me.
Dwarves masterietree is very clear, elves is ........ weird.
I do however like the buildings and city of the elves, though not more than those of the dwarves. So those, I think, were well designed.
Dwarven Mastery-tree is indeed easier for beginners to understand. After three servers I tried my hand at being an elf for a while, but the masterietree was just confusing (though that might say something about me personally too ).
Over the servers there have been quite a few (heated) discussions about the balance between the races. Devs seem to be playing and fine-tuning with them still. So, any conclusions made now, might not be applicable next server.