Mattermost sports higher performance, uses Postgres, is a pure server side application not using up too much of system resources on the client side, and gives an overall enterprise grade impression in general.
Updates go smooth without a hassle, everything is organised logically, and the integration with the OS is absolutely stable. Apart from that, the underlying runtimes and code are mature, proven and stable.
The developers are maybe a bit more cautious in regard to introducing new features, but they maintain a stable experience, not breaking the codebase in order to hastily implement bells and whistles, which are not yet ready for production. Documentation and debugging are fantastic, so running this in enterprise production environment is absolutely approved of.