This is an amazing game, I have spent around 200 hours playing it so far, and plan to spend many more. There are some negative reviews on steam, ect, and they were made by ignorant people who don't know how mods work.
Some negative reviews say that there is a terrible selection of songs, but really, there are thousands upon thousands of songs, if you know where to look. If you get beat saber on pc, (not psvr or oculus quest), you can install mods which allows you to play any song that anyone has mapped for beat saber, which is an insane amount. From classical music to someone randomly speaking into a microphone, the assortment of songs is awesome.
As far as the game itself, it is well designed, and is a great fun way to work out. You can listen to your favorite songs, and workout to them at the same time, and its actually fun.
Tldr, just get it