Minicars: Panda, Aygo, Spark, Splash....???

If you had 15,000 zł to spend on a small second-hand one-owner, entry-level city car - all things considered (colour, accessories, shape, mileage, etc.) - which would you choose:

Citroën C1, Fiat Panda, Chevy Spark, Toyota Aygo, Suzuki Splash, VW Up!, Škoda CityGo. Opel Adam ot other?
In that class what type of mileage is approaching the wear-out level a buyer should be wary of?

Basing on different reviews the Skoda CityGo seems a very interesting choice - affordable, economic car with decent quality. Check this opinion:
topgear.com/uk/skoda/citigo/verdict

Moreover I might still consider the VW Up! and Hyundai i10.

That would depend on the country I was in, whether the car was for myself or somebody with different driving style and ability, which mechanics I knew, what the car would be used for, etc etc.

Which hold up the best and have the highest resale value?

That much I don't know, however among smaller cars, the Nissan Micra is considered reliable and most importantly resilient if in an accident.