I rated this app a 5 because not only did the developer contact me in less than 24 hours, but the issue many are requesting- tempo adjustment- is being worked on as we speak & will be out with next update. There are other good apps out there as well, but adding tempo brings this up a level-it ahould be out with next update. As far as crashing, I have not had any problem with this. If you say you do, it must. I have found a reinstall will fix some issues. It also can be an ios issue or a carrier problem, i suggest contacting developer, if it is an issue, he may not be aware, but on my Apple 4s, with ios 6, it runs fine. thank you. This is a great app with a variety of patterns. What is missing, & very important to me, is the ability to increase or decrease tempo when listening to, or learning a rhythm. I am not great at reading & thats why slowing down would be so helpful. Is this possible, otherwise, everyone, it is a great app with many rhythms. Thank You