You have described exactly the two things about abook that have always put me off using it and drove me to build this. The ncurses UI works well but isn't what I want, and the "Yet Another File Format" addressbook format isn't very interoperable.
You're right that an exporter shouldn't be hard to build. Might get on that once some bugs and other features are out of the way!
One issue that will come up with any exporter: abook can handle multiple entries for each category, and (I think?) ppl can't yet. So, at the moment, I'm not sure there's a way to export without losing some information. Anyhow, I will definitely keep an eye on ppl. Looks like a very good start.
You're right that an exporter shouldn't be hard to build. Might get on that once some bugs and other features are out of the way!