I finally had a chance to test this first thing this morning. Two flights for about 30 minutes total.
As everyone else has said, they are definitely quieter, and lower pitched. The lower pitch was a little disconcerting at first because I know what my Air is “supposed” to sound like and it almost sounds like there’s something wrong, but I’m sure I’ll get used to that and this will sound normal eventually.
As far as how much quieter, very noticeably. The park where I fly has apartments somewhat close and I’ve always been a little nervous of someone being annoyed enough to complain about it. With these, I really didn’t have that concern at all, because it’s so quiet and frankly a little less “menacing” sounding (than the normal
MA noise before these props). At just under 300 feet up (the limit of my clearance) I could only just barely hear it; it was mostly covered by the early morning ambient birds and some traffic. With the stock props, it was easily able to be heard, as a curious guy pointed out a couple of weeks ago when he was surprised how loud it was even at 300’ (he wasn’t complaining, just curious, and given his interest I suspect he has one now).
No stability issues that I noticed, and it seemed to fly pretty identically to the stock props.
I only have a limited sample of flights to compare, but I didn’t notice that battery life was improved. After flying around a bit I brought it down at 15 minutes on the last flight and hovered a few feet away to see how much time I could get. I got 19 minutes, my longest time ever by 1 minute, but I was also trying to stretch it as long as I could until it landed due to critically low power, which I never do. Comparing stock-prop flight logs, I didn’t notice much difference in flight time at 50% battery left (actually, stock props had a slight edge). But I was also doing a little flying in sport mode to see if I got that current error, so that probably affected things. Will need to test this more.
Finally, yes, I did get the motor current error in sport mode. I kept adjusting the gain down (starting at 96, down to 92) and it always showed up, although at 92 it only seemed to come up after I’d covered 100 feet or so. I was also adjusting all axes, which may be unnecessary or even counterproductive; I need to do more research on this, and didn’t feel comfortable going below 92 without better understanding what I was doing.
Anyway, overall, yes, these are well worth the money for the noise reduction, but the motor current error continues to cause some concerns for those who use S-mode regularly. Since I do not, I’m happy with them.