Such a missed opportunity
I didn't use OS/2 1.x at the time (only later), but beyond 1.0 it was fine for server based apps and a good, solid platform. Not so much for desktop apps - insufficient driver support, high memory requirements, and limited app support put paid to that.
OS/2 2.x and beyond was a much improved proposition, but suffered in competition with the large number of Windows apps. The userbase were not, in general, prepared to pay more for a smaller amount of higher quality features - the reality of running a minority platform.
OS/2 might have got further if IBM concentrated on Intel, but instead they wasted vast amounts of effort on OS/2 PPC. Much though I loved OS/2, the succession plan was flawed. Windows NT is simply better architected, they spent the time maintaining compatibility with 16 bit apps, and had much improved security, and multi user support. OS/2 was effectively dead before it really caused a problem, but it would have caused issues later on.
System <n>/Mac OS were also flawed, and the early versions of OS X sucked, but Apple are much better at retaining compatibility whilst updating the OS (at least for a few years, until they drop old kit like a brick).
I've still got an OS/2 system, and a lot of apps, and will be assembling an OS/2 1.3 system (because I'm a masochist and like trying OS). Haven't bothered with eComstation, but might give Arca 5.0 a go if it's any good, and not ludicrously priced. There aren't too many OS/2 apps I really want to run these days, though.
One final note : it's *synchronous* input queue, not single. If messages are not taken off the input queue it hangs the interface, but does not stop apps running. There was a workaround implemented in Warp 3 fixpack 16, but until then a badly behaved app was a real pain. However, Win32 successfully moved away from the synchronous input queues in Win16, to asynchronous in Win32, without breaking too many apps. IBM should have put in the engineering effort to do the same.
There are also some substantial differences between OS/2's architecture, and Windows (or indeed anything else). For instance the co-ordinate origin in Windows is at the top left of the screen, but in OS/2 it's the bottom left (OS/2 uses the mathematically correct option here)