On 7zip it is free, does compression well and is available via Ninite. Likewise those using winrar can still decompress it and have been able to for years. Unless you need to make scene style archives or add new things to existing rar files there are no downsides to using it, no great reason to shift from winrar if you are happy with that either.
About the only thing it does not do is ACE files but if you have one of those then something has gone wrong, that and lzh but if you are dealing in those you probably know you are going to want something more dedicated anyway.
Back to the my external stuff might be better then at this point compression is more or a courtesy than a necessity, and about the only times I juice it are when trying to squeeze things just outside it into a 10 meg email limit.
Hmm. Is this discussion moving towards the idea of a patch librarian and branching version control capability (amid other thoughts)?
Normally I am all for feature creep, or "we are 90% of the way there"/story of GIT, like that but in this instance input file, output file, ignore input file hash are what I would go in for as far as required end user options, everything else being cosmetic/how much you want to thrash your equipment is what I would drag my heels for. I am all for version control being taken up by hackers, indeed I have seen several use GIT before now but I would want patching to stay its own thing.