My experience is that GS-mini more or less eliminates “hunting” by the auto thrust in gusty conditions. I used to fly regularly without auto thrust at my previous operator and I’m embarrassed to say that it usually did a better job than me. I think I’ve flown one approach without auto thrust in the last eight years, and that was only because it was decided that VLS-5 was its new favourite speed, in an A321 at max landing weight and conf 3.
The 787 auto thrust, on approach, is excellent in my opinion. It obviously biases speeds above vref, but in general is completely reliable and unobtrusive. The exception is on intermediate approach when it frequently seems to forget that it’s responsible for the speed control during level-off, even with the speed trend arrow going well south of the bugged speed.