I've dabbled a bit with OpenBabel and RDKIT, but I found their interfaces especially for simple things (traversing atoms/bonds in a molecule) quite unwieldy. I suspect that a big part of this could "just" be missing documentation / tutorials to get into it.
Maybe I'm just not deep enough into it, but from my impression so far especially when it comes to application-level software (in contrast to specialized research), OEChem and similar closed source libraries seem to be the most widely used ones, with nothing quite comparable available.
Context: Software Engineer that is also currently a biochemistry undergraduate.