[nmz]

In reality? None. Both give me lots of trouble. Red doesn't offer a good external program launch, which when things fail, I always drop down to sh. Rebol interestingly enough offers a wee bit more stability. but its age is clearly showing. r3 being open source has a bunch of versions and forks, none of them usable. there's also ren/c which is supposed to be usable, however I cannot build it on a pi4, there is also another attempt which is called arturo, written in nim, this one works but development is only done by a single person.