I would suggest taking look at Quick Base [1]. We've been using it for years and I've found it hits the sweet spot for us in the complex spreadsheet/light database space.
I've been following Airtable for a while and I have high hopes they continue their upward trajectory. I like where they are going, and they seem like the most likely alternative if we were to move, but Quick Base still seems to have a leg up in a lot of areas. Cross Application/Database Connections, Webhooks Support, and automated table sync from Dropbox/Box/SFTP just to name a few.