the only os ive never run extensively is macos- classic or osx. and i have programed for several systems, including dos, windows 9x and (very little) linux.
the best, smoothest, most capable, and most flexible preemptively multitasking system i have ever used is os/2 warp 3 and 4. i used warp for at ibm for quite a while, and warp 3 on my own personal machines.
i have never seen a warp machine crash, im sure they do but ive put several through torture and they never blinked.
i have preemptively multitasked, dos, windows3.x and os2 programs simultaniously with no slowdown and no comflicts even with the occasional dos hack crash.
fine tuning how you want specific programs to work makes it even better, and os/2 has an interprocess com like amigaos called rexx
so does any of that matter, do i run os/2 because it is so smooth and stable, no i use windows9x and xp. why?
because i use an os to run programs i dont run a computer just to run some really cool os. windows has better support than any other os both from ms and 3rd party.