Shininess? Who cares.
Now I know nothing about which is better in these regards but:
What would you look for in aerospace applications?
I would imagine things like:
Proneness to cold joints. Ease of detecting cold solder joints. Longevity (in general). Longevity under the stresses of aerospace realities. Etc.
Do you have data on that?
Those who care about the quality of the solder joint. You need to get a shiny surface, because anything else is a strong indicator that the solder has been contaminated/oxidized, and if it is such at the surface level, it may well be on the contact points aswell. Im not saying its a 100% garantuee, but if you look at failed solder joints, ESPECIALLY handmade ones, nearly all of them are the ones that were not coming out shiny. If its not shiny, its a fail
aerospace is a small part of what soldering is used for, globally. the majority is consumer electronics.
keeping lead out of people's homes is a valuable public-health move, not a needless "clusterfuck", as the comment I replied to said.
As a hobbyist I use lead free and I bet the rosin flux burning off if I make a boo boo is bad either way, lead or not. It's in both types.
About worker health in consumer electronics sure we can talk. But let's include the flux question in that too.
As for your hobbyist work, the flux used in lead-free solder is actually worse if you breathe it in:
It was widely believed that the move to lead-free soldering would create more environmentally-friendly conditions; however because of the higher temperatures required and extra flux used lead-free soldering smoke emissions actually contain more fine dust particles which are easier to breathe in. As Fig.1 shows, these penetrate further into the lungs than pollen or asbestos, reaching and blocking the alveoli.
https://uk.farnell.com/essential-considerations-for-managing...