Apple Dictation is the right default for short, direct dictation on Apple devices. It is free, already available, deeply integrated, and often works on-device. If you can say the text close to its intended final form, there may be no reason to install another product.
Rutta earns its place when speaking naturally is more important than dictating precisely: you want filler removed, corrections understood, longer thoughts structured, and the result made ready to use while preserving your voice. The trade-off is adding a third-party product and using cloud processing.