All software is “buggy” - from operating systems like MacOS and Windows on down. The more complex and polyvalent a system it is, the more it is likely to have bugs. This applies not only to software, but all systems in general. That is reality, what you want is utopia.
Rhino has been mature enough to do “real” work since it hit the market - its technical capabilities have increased over the years as computers, systems and people’s expectations have advanced. I have been doing “real work” with Rhino for like 18 years, it was the core modeling and editing software package of my own business starting in 1998. There are a bunch of other people in here who have been using it to do “real work” for as long as I have, and a lot of stuff you see every day - products, buildings, boats etc. have had at least part of their design done in Rhino.
Flawless, I don’t know… everything has flaws. The words incredibly responsive, highly skilled and human-oriented come to my mind first…