Turn mechanics

Hello JRPG enthusiast I have another question for you regarding turn handling mechanics.

I was wondering what your preferred method is for actual turn battles, not including action rpgs like the most recent FF, I'm talking about actual turn battles.

Regular turn handling:

Using a speed stat the turns are calculated everytime a round is completed

ATB:

This was extremely popular it consist of a bar that fills in real time letting you choose an action only when the bar is filled

There are a bunch of variations of these two but I want to hear what do you guys prefer