I have both metal and wood but as has been mentioned a lot depends on what lathe you have. With a cantilever bed, there isn't much to either because the base really is only important to hold the thing at working height.
What IS important is whether the thing moves out of alignment from ground changes.
I recall Tom Walshaw prattling about his workshop moving. He checked every month or so. There is a write up in ME under his pen name of Tubal Cain( somewhere)
Apparently, the earth moved.