This paper is concerned with the benefits of using rotational measurements of a gyroscope in conjunction with optical flow to determine the instantaneous rigid motion. It presents an experimental study focusing on three main aspects: speedup, resolving ambiguities due to local minima and accuracy. For this sake, we developed a method to minimize simultaneously the reprojected optical flow error and the deviation from the gyro measurements, in line with the optimal Structure from Motion techniques. We show that the gyro measurements can be used in a procedure to initialize the iterative estimation which results in a considerable speedup. We show also that minimizing both the deviation from the measured flow and the gyro measurements gives better results for the rotational velocity when the gyro measurements are not very noisy. It doesn't affect the accuracy of the translational velocity, however if the gyro measurements are very noisy it might lead to erroneous translational estimates.