The best app for those who are experienced in mindfulness practice and want to deepen their practice.
Brightmind describes the reasons you should meditate as:
Mindfulness isn’t just about relaxing and zoning out for ten minutes a day. Mindfulness is a sophisticated mind/body skill set, a new operating system upon which you can run your entire life. Yes, mindfulness leads to less stress, but that’s not all. You can learn how to meditate during an argument, gain insight into how your mind works, and increase your ability to make the world a better place.
Brightmind's standout feature are the journeys. I have done countless hours of meditation, and I still learn and appreciate the journeys. They really walk you through the practice of meditation in the most impactful way of have experienced. They are meant to be done in order, and I recommend that, even if you have been meditating for years.
They also offer a free subscription if you are in an organization that has as its mission to make the world a better place - that includes schools, nonprofits and corporations.
If you don't qualify for the free subscription, you can buy lifetime access or subscribe. Of course, there are free aspects to try out first (and I recommend starting with the 3 free journeys!)