Although Ongair and Callbell are similar tools, one of their main features concerns integrations. Ongair integrates with CRMs to manage leads while Callbell does it directly on its platform.
In terms of plans, the prices are similar, except for the fact that, if you decide to use WhatsApp on Ongair, you will not have any kind of help in activating the API; while, on the other hand, Callbell can walk you through the process or even do it for you.
Another big difference is that Callbell features automatic routing that redirects chats to the corresponding department, while Ongair only offers automated bots to manage customer interaction.