Comparison with Monica?
We're definitely solving a similar problem, and in the past I was a user of Monica until I found it too much work to keep up with. Monica notably does have more fields and performs functions (like journaling) that Dex does not.
Properly answering the question you asked is a whole can of worms, much like asking "vim or emacs" or "macOS or Windows or Linux" or maybe even "python or ruby or rust / go?".