The worst aspect is the sync issues with the app. The best aspect is having access to an EKG at any time. As a retired nurse, I am able to read my own graph. The ability to sync and send would be essential for most folks so I hope the app gets some attention. The device offers good variety of leads for analysis and I find the tracing much more definitive than the real time view on the device. I have had best results with sync to android phone and have app on iPad as well. No luck with direct sync to iPad but if sync to phone first, the readings appear on the app when app opened on the Tablet. Then, I save to files and can email from there. Overall, the instant access is valuable to me as well as not having to pay a monthly fee to use the app.