Very few people know about Mattermost right now unless they use or used Gitlab. Whenever I hear Mattermost brought up, it's associated with Gitlab, which has a reputation of being "the slower, less-good GitHub" (and I love gitlab, don't get me wrong, but I agree with that reputation). Therefore, Mattermost, at least in my circles, has a reputation of being "the less good Slack".
And the main issue (unless I'm misunderstanding, but I did go through your pricing page again to double check) is that you do not offer SaaS except to enterprises. Which is super backwards. You're not going to be able to gather mindshare if you require people to set up your product themselves to even just try them out. Nearly none of your potential users have the expertise to do that, and those that do aren't going to want to do it unless they know what they're getting into beforehand. The only remaining ones that already do are Gitlab users, because they've had it set up for them.
Github, Travis, Slack, Discord, Sentry, half of the integrations you find on GH, what do they have in common? They're hosted and free to try. Make a free hosted version, make it very limited if you have to and promote upgrades/self-hosting, and then you have a shot at getting solid mindshare.
On a lesser note, since you asked for feedback, here's a couple more pieces of advice:
- The demo video you linked me is great. I see Mattermost has changed quite a bit since I last tried it, for the better. So I visited mattermost.com to try and get another look and it's super barebones on screenshots, I found no videos, there's no demo. After browsing the site, I have no feel for what mattermost looks like. And you don't link to your community server anywhere I could find, not even on your contact page! - Consider making public Mattermost instances optionally readable without an account - read only, and enable that for your community server!. This would differenciate you from Slack and Discord and would improve the situation above. I realize it's a lot of work. - On pricing again, it's irresponsible to put 2FA behind Enterprise only. Please don't do that. Push notifications could also stand to be in the free version, imho.
Cheers, hope that helps. My email is on my profile if you want to talk about this further.