the ex1-mars has ABS brake function which is not readily available on the m8.on the m8,it's known as ALB and needs 2 b unlock.
i had experience with both controllers,basically the m8 is easier 2 setup.
but still,i prefer the ex1-mars...
not 4getting to mention that the m8 has a high batt power usage compare 2 any other controller around...