I tend to love ranking things. I think I annoy my wife by constantly asking her what her Top 5 x are. For cities, I tend to think in terms of which are just overall the most interesting, and which would be most interesting to live in long term (based on my salary which is relatively modest, roughly an ave. American salary).
For example, on the 2nd list, pretty much any American city would score a 0-3 b/c there are thousands of cities across the globe that are just far better to live in than the USA provided you earn an average American salary (and can benefit from earning in dollars with a decent exchange in many places). But even most Euro cities would score better than almost all American cities on that scale imo.
However, there are some cool cities: SF (back in 2010, not sure how it is now), NOLA is kinda cool, NYC, Chicago, etc. Those would score higher on the first list, but still wouldn’t approach the top quarter cities in Europe. I tend to highly value historical architecture, walkability, city design that invites people to congregate into plazas and parks, bike paths, public transport, etc. and if it’s at a non-ridiculous cost of living, even better.
Also note that I tend to love mega cities. The type where you feel like in a week long stay you’re just barely scratching the surface and you could live there a lifetime and still be discovering new things to do. So it’s also very difficult for a city that doesn’t at least have 2-3 million people to rank highly. One of the few exceptions would be Strasbourg. It’s fairly small, but I just love the vibe there so much (and in nearby Colmar).
As it stands now, I’d say my 3 current fave cities would be Paris, Rio, and Istanbul. Those would all get a 10. Next tier (9.5/10), very close to those top ones would be Amsterdam and London. 3rd tier (9/10) would be Prague, CDMX, Madrid, Barcelona. Probably forgeting a couple cities too.
Examples of 5/10, would be Marseille, Tbilisi, Bogotá
So from that perspective, I think I’d give Krakow an 8/10 and Warsaw a 7.5/10 in the overall city rankings.