SCO UnixWare caused me so many headaches in my IT career. I'm still dealing with that garbage in several sites. Slowly, I'm replacing everything with pSeries running AIX.
Oh yeah! Unixware is unmitigated CRAP!
As the lead admin in a 24/7 datacenter, I was tasked to roll out 250 call telephony servers running U/W 7.0, after six months and untold amount of headaches, I told the Company CEO that we were NEVER going to get it running correctly, and SCO's service and support is the pits.
I have had far better results with HP-UX and AIX on RISC servers in a fault tolerant mission-critical environment.
Don't even get me started on early versions of Solaris.