Much better than average audio quality, considering it was taken with a fancam. The small venue helped a lot, for sure. But halfway through it got bad and distorted, even painful (for my ears) at times. I’m not mentioning this just complain about fancams again. Some commenters mentioned their thanks for it, because they were at that concert, not close to the stage, and appreciate reliving it.
Meanwhile, I’ve seen mics go up in quality and down in price. The concert we heard above was recorded with a $180 mic. I think we’ll see fancam audio quality go up, at least in small venues without thousands of screamy fans. These new, more affordable “32-bit float” mics can record very loud music without distortion, and can be more easily processed to suit all audio volumes.