I can't answer for any of those locators. What I do know is even if you learn how to use the swivel handle/antenna (train your brain to be quiet) it does not guarantee that you will find anything of value. Might just be a mineral pocket.
I don't like the hand-held configuration. It is just not right. I realize it looks easy and convenient, but the real way is to place the transmitter on the ground and let the signal line build for five minutes or so.
Here's the Contraption I have been working on. Poor video and you have to look quickly at the start of the video to see the silver target I am locating from 50 feet away. You can hear a clicking sound when facing the target and a sharp null when turned ninety degrees.
https://www.youtube.com/watch?v=O0FIE0mGg7k