Titanium Chainsaw

The choice between the two is real, not cosmetic. The chainsaw cuts faster but reaches less far, so it wins when you are standing right against what you are cutting and loses when you want to clear trees or vines from a step back. For chopping out a jungle or working a tree farm, the extra reach on the axe usually saves more time than raw speed gives back. Around a base, the chainsaw feels better.

There is one more wrinkle. If you have already built a proper digging loadout with speed accessories and armor bonuses stacked, the axe pulls ahead again, since those bonuses do more for it than for the mechanical version. Neither is worth crafting if the next ore tier is close.