I like the vintage style better. No edges to dig in to your fingers (on the handles).
They got redesigned probably as a way to reduce the manufacturing cost.
The name "fast-gun" came from the fact that the handle was like what an old lever action rifle had.
Younger folk didn't understand the concept of "putting your hand in the loop" like you do when chambering a round in a lever action rifle. Instead, they'd grab the whole handle and then smash their fingers. Maybe that's why they got redesigned.