Poland, Czechia, Slovakia, and Hungary are member of the European Union, NATO, OECD, and are considered high-income, developed economies; while Ukraine is not. Ukraine is actually fighting for survival; is in an undeclared war with Russia and is considered as the most dangerous and unstable country in all of Europe. Ukraine lost 25 years of development and it is far behind the Visegrad group in all possible measures and indices.
To answer your question, yes, all Visegrad-4 (Poland, Czechia, Slovakia, Hungary) countries are nice to live in. They are developed, safe, and clean with well organized infrastructure, IT sector, public transportation, and utilities. Cities like Prague, Krakow, Wroclaw, Gyor, Bratislava are far cleaner than many western cities, including British Islands, France, Belgium, and entire Southern Europe. Dublin, Brussels, and Barcelona are far more dirtier than any other Visegrad-4 metropolises. Subsequently, Czechia has the lowest unemployment rate in all of Europe, while Poland, Hungary are not far behind. The job opportunities in all V-4 countries are numerous and there is a labor shortage in many sectors of the economy.
Czechia is the best country with the highest level of development, least restrictive government among EU members, and sixth the most peaceful country in the world. Its per capita income has reached 90% of the EU average, just below of the Spain, and above of Portugal and Greece. Prague is also the fifth most visited city in Europe and it is also a hub for many western companies. The crime level in Prague is 1/3 of that to Stockholm. Overall Czech Republic ranks well with social, healthcare, and educational opportunities, often to be placed along the level with the other Northwestern Europe, and pulls between 15-25 rank globally. However, the drawback is the relative low salaries, bureaucracy, and poor services.
Poland is the most diverse country, where there you have high-income areas and one the most rural, conservative provinces in all of Europe. It will offer due its size most historic landmarks. It has coastal areas, large castles, well preserved historic cities, rugged mountains, marshes, and deep woods. However, Poland has made a significant progress in the past 25 yeas, its infrastructure has improved, and its services are better than in the other three countries. Bureaucracy is terrible, and Poland lags behind the healthcare, and social services. It is also socially conservative, more than the three other V-4 countries.
Hungary is generally ranked high; however, it went through prolonged recession, which caused to fall behind Slovakia and Poland. Budapest in the 1980's was considered the most Western-looking city in all of the Eastern Block, and was a favorite place for many western companies. This advantage was lost during the Great Recession. Budapest is very cosmopolitan (second largest city in Central Europe after Berlin), and is less expensive than Prague, Bratislava, Warsaw, Zagreb, or Tallinn. Forbes, placed Hungary as one the best destination to retire. Western Hungary became popular for many Westerners to retire, and its medical facilities are good. Hungary from all V-4 has also the best climate, with long, hot summers, and short cold, winters.
Slovakia combines the best and the worst of the V-4. It is also the only country that is a Eurozone member, which made it far more expensive than its neighbors. Bratislava is considered sixth wealthiest city in in the EU, with per capita higher than Prague, Paris, or Berlin. However, eastern Slovakia is very underdeveloped, dragging the country average down. Slovakia has far less historic landmarks than Czechia, Poland, and Hungary, but it has the most spectacular mountain scenery. Bureaucracy, poor services, and underdeveloped healthcare system made Slovakia less desirable than Hungary or Czechia.
In summary, with a comparison to Northwestern Europe, V-4 are still behind it and less desirable to live in it than Germany, Netherlands, or Scandinavia. However, it is far easier to live there than in Southern Europe, if you do not care about Mediterranean climate and beaches. The region developed rapidly in the past 25 years, and has a high growth rate, which indicates that they will overtake Spain and Italy in the next 5-7 years. The social and political changes are less possible and the region will remain in the foreseeing future as the illiberal block within the Continent.