I mean ... I used to write software in C that targeted AIX as well as HPUX, Solaris etc back in the 00s. It was fine. Posix compliant, had a C compiler, debuggi

I mean ... I used to write software in C that targeted AIX as well as HPUX, Solaris etc back in the 00s. It was fine. Posix compliant, had a C compiler, debugging was OK with dbx (IIRC you could get ddd to use dbx as its subordinate debugger, which was helpful). The main selling point AFAICT was that it was on POWER, which has always been a pretty competitive set of processors, often faster than x86/64 in some (no doubt carefully massaged) metrics. I think, like a lot of IBM systems and a lot of commercial unix, at that point it was ahead of the game in its system-paritioning capabilities, having LPARs much like z/OS (and Solaris Zones I guess). I don't know if it has any other major unique selling points, as a C programmer I tended to focus on commonalities rather than differences!