I always liked the RF, but preferred a hardtop and a less common car. So, it depends on what you want. From I've read, the Miata has a nicer engine character and song. Apparently, the RF (edit RF Club) is the higher performance model, and I wanted the most pleasant street ride, which the BRZ delivers (even compared to the GR86) because the rear is softer and less tail-happy than the GR86. I'm 5'10", and getting into the BRZ involves folding at the hip to get in and out. Once in there, it's comfy. There's a high end tS, which compares better to the RF, but I wasn't looking for a stiffer ride or track days. Car and Driver compared these two, but it's a different comparison fo:r less high-strung models:
https://www.caranddriver.com/reviews/comparison-test/a61008331/2024-mazda-miata-rf-club-vs-2024-subaru-brz-ts/