Personally for me it's missing key feature - selectable, custom sounds (already working in Pushover) This allows to mentally prepare for situations like production down is much more important than home automation done and I want to instantly distinguish between them, not have heart attack every 1h.

Desktop app would be really nice, even in Pushover there is a lack of ability to get notification on my desktop and dismiss them both on desktop and mobile. Only strange web version with separate notification stream.

Price of myNotifier also seems pretty high vs Pushover, considering it doesn't have more features.