I'd choose your magnification based on the closest possible living/moving target you might be engaging.
You are gonna have a hard time picking up a deer at a fast trot at fifty yards with a 10x--the scopes field of view is gonna be way too small. Unless the deer is walking in a wide open area or something.
If the closest thing you might be shooting is a coyote or groundhog at 200 yards, 10x works fine.
For hunting I have a fixed 4 and a fixed 6. For target shooting I'd say a fixed 10X is the way to go. Fixed 15 to 20 and you end up with less eye relief and a smaller field of view, anything less than 10X and it starts to become "too little" magnification. 10X is a good in between.
Also you will have no problem selling a fixed 10X tactical scope whereas the higher power fixed ones have a very small selective market.