Hi Paul,
Thanks for contacting me here.
I’ll try to answer your questions here…as they are posed, it’s hard to do so in a “definitive” way…
Which one is more complete?
Both AWPCP and BD have been around for years and have had continuous development. We have an open-ended issue list for both and continue to work on new features as well as fixing existing issues with similar regularity. I can’t really call either “more complete” than the other because they’re never ever going to be “done”.
Which one is more robust?
Both plugins are very mature, so this is also a question that isn’t easy to answer. If you’re on a modern version of WP, with a late version of PHP, updated plugins and themes that are well-coded, then both are equally so. In practice, other plugins and themes can affect the robustness of ANYTHING out there if they are coded poorly.
Which one has more features built in?
You can see our feature lists here:
https://businessdirectoryplugin.com/features
And here:
https://awpcp.com/features
I haven’t counted the features in either plugin for a long time and it’s not as interesting as what features you and your users need the most. Can you answer me that?
Which one has more premium addons?
You can see our add-on lists here:
https://businessdirectoryplugin.com/premium-modules
And here:
https://awpcp.com/premium-modules
Each one targets the needs of the users for that type of listing engine–AWPCP is more classified oriented, BD more directory oriented…
The one that has more isn’t necessarily the one that fits your needs more closely.
Which one is more recently coded and might have a tighter structure?
etc
Both have recent updates for WP changes (such as 4.5). AWPCP is undergoing a migration to be a full custom post type right. BD has been a custom post type since 2012. So in that sense, BD is more “modern”, but this situation will be remedied within a month or so and they’ll basically be the same.
I hope that helps. Please let me know if you have any other questions.