... I hear the Sony DSLR forum regards them as the spawn of hell, for example.
eh??? The Minolta Dynax/Maxxum mount (which is the Sony a-mount) easily takes M42 lenses with a glassless adapter - with no infinity focus problems. Dunno where you got that info from. There's a whole subforum on Dyxum.com dedicated to M42.
There is nothing, absolutely nothing, half so much worth doing, as simply messing about in boats