What are some alternatives?
When comparing SHAREit and Pushover, you can also consider the following products
Send Anywhere - Send whatever you want, wherever you want
Pushbullet - Pushbullet - Your devices working better together
FilePizza - Open source application used to transfer file via WebRTC and WebTorrent.
AirDroid - Access Android phone/tablet from computer remotely and securely. Manage SMS, files, photos and videos, WhatsApp, Line, WeChat and more on computer.
Dukto R6 - Dukto is an easy file transfer tool designed for LAN use.
Gotify - a simple self-hosted server for sending and receiving messages