FWIW I find vipasana (just focusing on your breathing) so much more effective than those apps, particularly Headspace. Calm with a little background noise and timer is fine. But with Headspace I don't see how anyone can meditate effectively when the guy is talking to you the entire time. Especially when he counts your breaths occasionally and your counting is out of sync with his.
During sessions, he stops speaking for many minutes, to let you focus on the breath. I found it useful at first, because I saw it as hand-holding. I couldn't focus for very long at the time and this helped.
When I developed more focus, I stopped using Headspace, so I could have longer periods of uninterrupted silence.