The biggest difference between leaf joys and micros is that you can feel the corners on most micro sticks.
Wico 8-ways have a round actuator on the bottom that contacts the long leaf springs; and, more importantly, a round guide hole inside the stick base.
This produces a completely round feel to the stick, where you can't feel yourself going from one switch only to two switches in the "corner" of the stick.
If you move the stick in circles on them, it feels like it is going in a circle.
Most micros use a square actuator, and most of those that don't still have a squarish guide hole on them, so you can feel the corner on the stick.
If you move the stick in circles on these, it feels like it is tracing a square.
Some games require that you be able to quickly hit the diagonal to pull off moves, other require that you "sweep" a range from say up-up right-right to pull off the move.
For games that you NEED to feel the corners on, the micros are probably the better choice.
For games that you need sweeping moves, the leafs will probably work better for you.