That's tough, because size is a personal preference. I personally enjoy and prefer larger folders, so when I was making the same 8 vs. horseman decision, I chose the 8.
Now if you feel the Commander is a "pretty big knife", you're probably better off with the Horseman.
The 8's handle and blade are longer than the Commanders, but skinnier and more compact when folded, which to me feels smaller and is more comfortable in my pocket. I don't own a Commander, but the same holds true when compared to my ZT 561. The 561 is shorter, and thinner than the 8, but when folded is much wider and feels bigger in the pocket. Judging from all the comparison picks I looked at when deciding on a Commander or 8, the smaller Commander would have felt bigger in the pocket.
Anyway, that's how I decided on the 8, and I'm happy with the purchase. Hope that makes sense.