I find 5 least consistent because there are now two competing ways to define an unnested block: the normal way, and the `@nest { & { ... } }` way. Why would anyone do the second way, you ask? Because that rule used to have a nested rule, and when it was taken out the programmer was lazy or didn't notice that it was the last nested case. Having to completely reformat the base rule just to add or remove a nested case is a complete deal breaker for me.

I started liking option 4 when I started thinking of `} {` as a special "nested stuff here" sequence instead of a set of scope delimiters. True, it would be better if they had used basically any other sequence of bytes for that, but it still bothers me less then that goofy `:is()` requirement.