I live above ground after I have gathered enough materials for a decent base. I usually with start in a cave for a while, then move to a decent sized structure at least 19x29 in size with two levels. Then once I have a quarry and some other automation, like a tree farm, I'll go all out on a large main base.
I generally try to build above ground because I like to build cool structures. I usually end up with a basement when setting up long term power generation. I put the boilers, or failed attempts at reactors in a basement because I don't want to blow up the main structure, and I get frustrated with pipes and wires being all over the main base.
My current base was built after a looong time living in a cave. I plan to eventually run AE lines everywhere, so making them look nice is going to be a challenge.