Bloomberg has published article titled The Best and Worst Places to Be in the Coronavirus Era. Their Covid Resilense Ranking covers 53 countries and the top 5 is:
1. New Zealand
2. Japan
3. Taiwan
4. South Korea
5. Finland

These results show that the top spots go to countries with quite strict entry requirements, so heading to these countries just now might not be that easy.

And additional note regarding Finland: there has recently been a surge of cases and as thus parts of the country (most notably the capital region around Helsinki) will face more strict measures to curb the infections, eg. no public events for more than 10 people and various places closing temporarily.