This comes up from time to time usually involving 3 cities, but I will expand it to 6 cities.
The OP cant make rules, but I can make a request: we keep this in a positive tone. So restrain the negative comments and expand on the positives of each. It’s not a competition but, maybe an explanation. Different people are attracted to different environments, activities, histories, etc.
1. What is your favorite Central/Eastern European Capital City in this list. Prague, Vienna, Budapest, Bucharest, Sofia, Kyiv?
2. EDITED: For the city(s) you have visited, what sort of tourist/traveler will enjoy it the most?
3. Is one, or more, better for a quick visit or living like a local, or museums or …. (?)
Since my primary preference is obvious, I will restrain my comments on that one city.
We can probably have fun with this and I might learn a bit more.