There is a trade off between speed and quality with x-y laser cutting. This 80# cardstock test shows a slow run on the left and a fast run on the right. To get the best results I run the laser at a slow speed; it ensures very smooth curves and a close representation of the original art.
At a fast speed the laser beam carriage runs with some wobbles. If this loss in accuracy is acceptable for your project please let me know. Depending on the circumstances it may lower the cutting cost 10-50%.