In my experience, standover height on a MTB is lower than on a road bike, but the pedal-to-seat height difference is made up for with a longer seat post. I've also found that I was stretched out more on my MTB than on my road bike (until I got a long top-tube road frame). My MTBs have also always had longer cranks (175s) than my road bikes (170s). I ride each bike differently, though, as each type of riding requires different skills.