Has anyone used both of these applications and found a preference?

It seems like the salesinbox is made to integrate directly with the CRM (which is a plus for me). However, it seems like TeamInbox has been getting more development lately?

And they do not seem to be connected in any way. Trying to figure out which would be a better option for my team as opposed to something like Google Workspace (the downside being I lose out on connectivity with Zoho CRM).