Yes, I have. As I wrote in the sibling comments the last time just a week ago, the actual train that’s being discussed here. I’ll be again on Friday, for the return. I’ve taken multiple other night train connections before and in my experience, the quality depends to a large extend on the operator and the rolling stock. Older stock makes for less comfort, especially if not well maintained.

In my experience sleeping on the train also takes a bit of getting used to. Then again, maybe it’s really not for you - that’s ok.