I see that there is newly spiffed up Allwinner wiki info!
I last paid attention to RPI a few years ago and am about to install a
machine or two. It would be really nice if the RPI page
https://wiki.netbsd.org/ports/evbarm/raspberry_pi/
explained about the RPI3, and whether 7, 8, and current work. (My
impression is that 8 and current are fine on RPI3, but not 7.)
At this point I am not finding 7 of much interest for new installs
unless there is concern for production stability. But I am unclear if
there are good reasons to run current instead of 8 on a PI3, if what I
want to do is random normal stuff (use a USB disk to be a semi-NAS), and
GPIO, including I2C, for attached sensors. Overall, I'd rather stick to
8 on machines that I want to use (vs test current on).