My Ideal tester had a bit of a "learning curve," but I got pretty good with it untill it broke.
The replacement Gardner-Bender (similar price) has been easier to use.
When I absolutely cannot risk tripping the wrong breaker, or electrical noise makes the tone units useless, I get one of those old-style 'buttons' that people used to put in light sockets to make the Christmas lights blink. I then use my clamp-on amp meter to look for the circuit whose draw is regularly fluctuating by half an amp (60W bulb).
