The MPU is considered the old-and-stable option, but is limited to and 8k update rate. If I remember correctly, the ICM gyro will go up to 32k, but are supposed to be more prone to noise. Some manufacturers used ICM gyros for a while, but a lot switched back to the MPU.

Now Betaflight has dropped support for 32k looptimes, the ICM is looking even less attractive. Having 2 may mean they can filter out the noise more effectively, though.

MPU6000 maxes out at 8KHz, while the ICM20689 can run up to 32KHz in Betaflight. But when you enable 32KHz mode on ICM gyro's, they are known to be noise sensitive, not so much when you are only using them for 8KHz though. MPU6000 are known to have less problem with noise.

However, since Betaflight 4.1, with 32KHz mode removed, the highest looptime is now 8KHz, so it isn't that big of a deal anymore which gyro you choose.

here is a bit more info about flight controller gyro: https://oscarliang.com/best-flight-contr...pter/#gyro