Dual IMU and dual Compass on P4 vs Single IMU and single compass on P3? Which one better? whether with dual IMU and compass capable of repairing Flyway and less crash?

Hello,here is the advantage of dual IMU and you can learn more specs in our official website：http://www.dji.com/product/phantom-4

But please keep in mind that it is very important to select an open area for flight and do pre-flight checklist：https://www.youtube.com/playlist?list=PL8-vxWY64sBOmkQQJ2KWNL-uRBZsP43-r

Of course more is better, unless it's your wallet doing the talking.

Generally in engineering practice, fail safe systems often have "triple modular redundancy" engineered into the product in order for it to be considered a reliable system. So the phantoms are still one set of sensors short!