Copper might be a bit more popular than SOGo. We know about 1 link to it since March 2021 and only 1 link to SOGo. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Episode 3, which I will bookmark as it lists the solutions that they have selected. I read e.g. About SOGo and Zorin OS that I didn't know of. Source: about 1 year ago
I've seen Copper CRM work quite well for contractors (assuming that your team is using or open to using Google Workspace - if you're not using Google Workspace, I'd probably ask why not? But then recommend you to use Pipedrive if you're not willing to switch to Google Workspace). Source: over 1 year ago
Roundcube - Web-based IMAP email client
Zoho CRM - Omnichannel CRM for Businesses of all sizes
Zimbra - Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.
Pipedrive - Sales pipeline software that gets you organized. Helps you focus on the right deals, so easy to use that salespeople just love it. Great for small teams.
Rainloop - RainLoop is a web based email client.
Freshsales CRM - A full-fledged CRM for high-velocity sales teams.