They dry almost as soon as you take the heat off, which keeps parts from moving off their pads while it dries. And the iron doesn't seem to "pull" globs of the stuff around as much. I get really frustrated doing finicky work with leaded solders, but I'll happily do 0.5mm pitches by hand with lead-free.
Maybe it's just because I learned with the stuff?
What has evolved a lot since the pre-RoHS lead-free panic (2002..2006) is synthetic flux. Hardly see rosin based fluxed in industry nowadays (where performance matters).
For DIY stuff I mostly use SAC305 solder with synthetic mild flux (REL0) like LF4300 (water soluble, in theory no clean, but you do not want to leave this working in very humid environment) or SMD291NL (true no clean). In production different ones depending on the end product and components. Activity and cleaning requirements are main characteristics to choose by.
In the custom keyboard hobby you often have people desoldering 160+ through hole joints. With good tools (Hakko FR301) and good solder (Kester 63/37) that's a 15 minute job, but the frustration level and time commitment increase significantly as your tool quality or solder quality declines.
How would doing a whole keyboard of lead-free compare? Especially if you don't have $300-500 invested in gear.
Another question is, how's quality of life on surface mount components in a home/DIY setting? Obviously industry has no trouble here, but sometimes you need to do 0602 or a TQFP by hand.
I use kester 66/44 eutetic tin-lead solder on anything I care about.
It's said that light-dark auto helmets make someone a welder nearly overnight; I think that same way about eutetic solder and soldering, it makes the job so much easier that the quality of the work skyrockets.
in racing, they say to drive 10/10ths. not 1's. for the same reason.
Lead free behaves differently for sure (although how exactly also depends on the mixture, iron power, temperature), but as you I actually find it better and not worse.
And I think I've seen tin whiskers once in 20 years. I'm dubious it's a problem for 99% of commercial applications. Unlike mil spec the temperature extremes are less, IC's are encapsulated[2]. And I suspect lead free alloys aren't as problematic as pure tin.
Either way industrial production, processing and eventual disposal of lead is bad news.
[1] Nicest solder I've used is lead/tin/antimony. Stuff was the shit.
[2] Early papers I read were all about pure tin solder causing problems inside hermetically sealed packages.
Quite possibly. I learned to solder last century, using leaded solder, which was available in copious amounts in my dad's workshop for a long time, throughout my high school and university years. It took me a few weeks to get used to lead-free solder and it was days before I could solder anything correctly. I pretty much re-learned it. I sat for two days and did nothing but solder stuff at random until it started coming out right again.
Then a few years later I picked it up again with lead free solder and suddenly it was super easy and the solder flowed exactly how I expected. I'm not very proficient at it but since then I never messed up a pin.