Always a compromise. I have a SWFA 1-6X on my varmint AR. It is very effective out to 300 yards and at 1X it is fast for those pop up target. That said, I still want a little more magnification for the precision shots. Either will be fine for a broadside shot, but I don't see many of them. The higher top end would be nice when you are looking to slide a bullet between some brush or right behind the shoulder and even at 3.5X on the low end, it is still very usable for close/moving shots.

Given the ranges you typically take the shot from, the 3.5-10X sounds like the better option.