What are some alternatives?
When comparing CellSend and Join, you can also consider the following products
Pushbullet - Pushbullet - Your devices working better together
Pushover - Real-time notifications on your Android, iPhone, iPad, and Desktop
AirMore - AirMore is a cross-platform toolset that can help you manage any Android device wirelessly.
QPush - QPush is a free service that lets you easily push text and links from PC to iPhone.
KDE Connect - Integrate Android with the KDE Desktop
AirDroid - Access Android phone/tablet from computer remotely and securely. Manage SMS, files, photos and videos, WhatsApp, Line, WeChat and more on computer.