Originally Posted by
FortHay
DB is extremely reliable. Your 2.5 hr buffer is plenty in Frankfurt. While trains ARE occasionally late, cancelled or re-directed to other tracks, DB keeps you well informed. Connections to Dresden are frequent, so, even if you miss the planned train, there is likely another connection just about to leave. After arriving in Europe, Germany in particular, I rarely rent a car and never fly.
As the OP got satisfying answers to his question, I think we can go a bit OT.
No DB is not extremely reliable. They are somewhat reliable. A search on your favourite search engine will reveal plenty of press articles in German and foreign press about how DB has become a national shame due to their poor reliability and customer service.