alt Hacker NewsMacs do sleep well, when they manage to sleep. Sometimes macOS takes issue with certain programs, the last stack I used at work had a ~50/50 chance of inhibiting sleep when it was spun up.
All in all, I've given up on sleep entirely and default to suspend/hibernate now.
A buggy program preventing sleep is a bug in that program, not a mark on the overall support and reliability of sleep functionality in macOS.
There are valid reasons why a program might need to block sleep, so it's not like macOS is going to hard-prevent it if a program does this. Most programs should not be doing that though.