I have traveled many times on DB ICE trains, mainly from Nykøbing F (In Denmark) to Hamburg or Berlin. I have tried booth First Class and standard. First class has some very good seats i have sat very well in them, but the standard seats are also great seats. I never tried the on-board restaurant so i don't know about the food on it, but there is loads of good shops at Hamburg Hbf a few of them have good views over the tracks (See picture).
As far as i know, the train from Hamburg to Munich can be every ICE train expect the ICE-TD, if you know what ICE service you are travelling on eg ICE25, this
Wikipedia side will give you an idea of what it is. I have myself been on ICE-TD, ICE1, ICE2, and locohauled IC stock, all great trains, i cant compare them to any UK express train as i haven't been on any.
I know Hamburg well, so if you want to know anything about Hamburg let me know

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