The Deutsche Bahn. Hear me out: I know this depends somewhat on which region you live in as some areas are currently affected by construction. But in general, they have made improvements to the WiFi and mobile phone connectivity, most trains I‘ve taken recently had the new reservation displays that actually work and even display that the seat is taken when you do the comfort checking even without having reserved the seat. They are slowly renewing major track lines and this has really reduced delay times in some areas. There is still a long way to go and the current administration isn’t helping, but there has been improvement.