Forgive me if this has been covered before but doing a search I didn;t see anything.  

My question is, what are the best brands/types of quick removal mounts that will do a good job of holding zero?  I am basically looking for a system that will allow me to swap out my EOTech and my scope on my M4 flat top without loosing zero on either.  If possible I would also still like to be able to co-witness my BUIS through the EOTech but that's not a huge priority at this time.

Thanks everyone!

+1 for the Larue the best there is IMO, the new one's come with a lock on the throw lever, not shown in the pic

Thanks guys!