The best one I have use was Istanbul-Thessaloniki (Turkish one was new, clean & spacious; Greek one seem to be an old french train but both were for 2 persons). Istanbul-Ankara train was nice as well.

Vienna-Milan from trenitalia was ok. Vienna-Cologne was good but it was so expensive, i just got inclined seat.

Hope these trains will make a better come back.

I hope so too. The Asian train hospitality will never be beaten by OBB (I am in neutral grounds, so I dare saying I am being objective), and same with the comfort feeling of the "mattress". Interestingly, Turkish Airlines has IMHO the best food for tourist class.

I got practically no sleep on mine since they just had me in a standard cabin (like in Harry Potter). Bench seats are just not for sleeping on. It would be much better off with airline or Amtrak style seats.

Yes indeed, Amtrak seats are more adequate for a night train.