I've used all of those when they came out. SunView was presented to me as the default and was all I used until X11 took over. MGR was awesome and almost certa

I've used all of those when they came out. SunView was presented to me as the default and was all I used until X11 took over. MGR was awesome and almost certainly the easiest to develop for. I really regret MGR didn't get more traction. Note, MGR worked over terminal connections like rsh, unlike the rest of them (X11's hackish DISPLAY not withstanding). OpenLook (and NeWS) were dog slow on the humble hardware (IIRC) so I never used those in anger. X11 is such a kludge, but a useful one, so it took the market I guess. I suppose Wayland is the future but AFAICT, it's even harder to develop for than X11.