Just tried it for 5 minutes, the UI looks really clean, the UX is not the best though. I've been trying to add contacts with the "batch" feature, I tick some checkboxes expecting to add them to my list, but there's no apparent way to do so. They stay checked and I don't understand why and what that means.

I'm not sure what "mark people as in touch" is, and to me it sounds the same as adding someone from your contact, but it looks like this is a different operation from adding a contact to the list.

I like the "more" tab and its contents.

Out of curiosity, as I'm interest and work in UX, did you test this app with some real people / how did you test its UX?