Ideally, neither!

My expectation would be that for quite fixed structure trees, an interface based tech tree would look and update much nicer.

For very dynamic tech trees, I would imagine that a HUD-on-map style tech tree would be more flexible, and ultimately less effort to implement.

Performance-wise, I would hope (perhaps naively) that both would perform quite well if done correctly and with proper thought given to how you are updating and re-drawing the tree, with the interface based tree probably rendering with less effort and better response time for the user.