How to choose a refrigerator?
1 features - subjective. Capacity, outer dimensions, ice maker and water, etc. have no right or wrong answers and depend on your specific needs.
2 compressor - information not readily available, in my experience
3 tubing - inside refrigerator information not readily available, in my experience. Outside for water for ice maker - up to you, not determined by manufacturer.
4 and 5 - efficiency - in the USA look for EnergyStar ratings.