There are numerous MCUs which would meet your requirements, PIC, AVR, MSP430, etc. However, many of the IMU Sensor Boards that I have come across utilize an AVR. Therefore, the abundance of code examples for this specific application maybe skewed in AVRs favor.
The most important factor, after the ability of MCU to meet the applications requirements, in making your choice is your comfort level in coding and developing for it.
I suggest, before making your choice, you Google for similar projects and see what would be easiest for you to adapt to your project's requirements.
BigDog