I had a Naida, now have a Marvel. The difference is night and day. The Marvel is hands-down the best hearing setup I have ever had (I am mid 50's, have worn aids of one type or another since I was 3 yo). Bluetooth is a game changer. The Roger On is fabulous in meetings and with computers (it appears as a USB sound device, it's far more reliable than BT for that). Battery life is fantastic, it lasts more than a day, and there's a fall back to disposable cells if required. Mobile app is a bit 'meh', but the rest is so good I can't complain!