I think this would save bunches of hair torn out by users, especially when they're working with new (or alpha/beta) builds that don't give away yet how they will behave...
SoulseekQt would then crash, but sometimes even leave a "chance" of a corrupt data file.
While I can't appreciate it enough that you fixed this problem *ON SUDDEN CRASHES* in the January 2013 build, the user (and me too) might still be interested in tucking away their config file some hours BEFORE,
They could have made a time-consuming setting like application colors, and ... chances are they'll be left with the old colorset afterwards.
Why am I so sure? Well, since I've repeatedly tried to "tuck away" my config file when Slsk was running, I can now say that the <em>settings in their entirety/en> will NOT be saved until the client is fully quit. My "proof" is that I did make said color settings, and then copied my data file (Slsk still running).
Then I quit Slsk violently with "killall".
Since I backed up my settings BEFORE terminating the process violently, relaunching SoulseekQt should leave me with a fully-working configuration file.
The config *WAS* working, but the color settings were stone-old.
This could be one reason why it's very useful to <em>manually</save> the config file from time to time. Since this makes the user independent of everything to come/to occur.