H1-B is a form of servitude. As a product manager who lead a team of primarily H1-B engineers at a large bank in DC area, the most challenging thing I saw from my H1-B colleagues was how the H1-B visa essentially forces really talented and amazing engineers from venturing off to more interesting opportunities at smaller companies who do not have the money or legal team to support H1-B employees.

My former colleagues are all limited by their employment opportunities and could really only go to a handful of very very large firms that would sponsor their visa's. It limits their employment opportunities and it limits their mobility.