I'm not sure if anyone from our group responded to your question. Thank you for the note and I love that you've already been laying the ground work for mindfulness in your school! There are tons of great apps out there, and some of figuring out which is best for you is to try various ones to see what works best for you and your students.
I would say one key difference is that our approach is very focused on daily practice. The idea is that mindfulness isn't really a strategy to use when things get crazy (although it can work in that mode), it's really the development of a daily practice that helps kids regulate so things don't get crazy as often. We love Dan Siegel's analogy about teeth brushing. You don't brush because you have a cavity, you brush to avoid a cavity. Most children brush and understand why they do it. We suggest to them that mindfulness is the same thing. You do it every day to promote cognitive health. This isn't a program as much as it's something you do every day, hopefully throughout your entire life.
Due to this focus on daily practice, we created a series that follows MBSR and which has been proven through 3 scientific studies to improve grades, test scores and behavior (and to reduce teacher stress). Most apps don't have research on their program, they use research about mindfulness to suggest their programs will be effective too. This may be true, but you won't know until the research is done on the specific apps used in specific ways. Generally teachers tell us they love our format because it takes all the planning out and they log in and each day is something new (and it builds the skills as the series progresses). Having said all this, I think it's amazing that so many tools are available so that teachers and their students can discover what works best for them each day. You can run a trial of our program to see if it fits (probably next year since the school year is about over in most areas). Please let me know if you have specific questions. With warmth, Laura