Emirates has one of the world’s best first class products. Their business class wouldn’t come close to ranking, and their new first class is only on a limited number of planes. But their decade-old first class, while a bit tight on space for its fully enclosed suites with doors, is still a marvel with great amenities, good alcohol and catering, and generally good service.
It’s very very available using miles. Perhaps that’s because there are so many first class seats on so many flights and very few people know how to redeem for these seats at a reasonable price.