The service is free of charge for most of us and all is in beta stage. I would not use it in an productive environment at the moment.
The buisness model of tutanota is somewhat similar to.the e foundation (donations, premium subscriptions). But they focus on e-mail only not on entire ecosystem (operating system for 90+ devices, cloud, …). To fund employees with a decent income is quite a challenge. If I look at the numbers of tutanota and posteo and compare them to e it must be tough for e.
I guess if more people pay then e can hire sustainably staff that fixes issues fast 24/7.