Currently I am on 7.5 horiz and 7 Veritcal, and 8 Accel. You want to keep your acceleration quick for turning around, and horizontal helps with that too, so having a good balance between how fast you want to turn around and how well you control your horizontal aiming. I think a fast accel is important, and finding a good horizontal is hard, 0.5 really makes a difference to me.
Now on the topic of vertical. This only really affects me when you are jumping (downwards or upwards) and the opponent is jumping as well. Imagine your target is below you, and you drop on them, but as soon as you drop, they jump -> now your target is moving upwards while you are moving downwards. Currently a 7 vertical would not be fast enough to kill a skilled player. You would need something like 8.5-10 to clear that feat.