4 maps/modes on both but I think the programming is different. Not significant differences, but the EX programming is more suitable to trail riding and the MX is for MX track racing. I demoed a 2017 MX and then bought a 2018 EX. I didn't notice a difference, but I didn't ride them side by side and I am kind of a wimpy rider, my goal is to not get hurt vs fast all out speed. I normally just ride in map 1 or 2 so there may be more noticeable difference in map 4.