Both are a Sentai team that uses elemental/magic power. There's another world that provide their powers (Magitopia/Gosei World). The Goseiger team isn't made by a family of heroes like Magiranger, but two of them are siblings. The two of them also have non-human sixth rangers (although MagiShine has a human form).
It's the 33th sequel of the series from Super Sentai right after Samurai Sentai Shinkenger which is the 32th sequel. If you would like to watch the super sentai series chronologically.
It's the 34th sequel of the series from Super Sentai right after Tensou Sentai Goseiger which is the 33th sequel. If you would like to watch the super sentai series chronologically.
It's the very first Super Sentai series what made many of it's successors possible. If you want to watch the original first season of the Super Sentai series.