I don't have an A3, but I do shoot the HTG and A2. Like them both.

I like the handling/carrying characteristics of the HTG over the A2, due to the more slender shape, and shape of the pistol grip. More comfortable two-handed carry, and faster to the shoulder. The comb is a tad low, but I do not find that a hinderance except in the prone/bipod, but keeping glass low, and adding a stock pack solves that.

The A2 with it's high comb, and near vertical grip, is super comfy/ergonomic to shoot, but a little less comfortable to carry.

For traipsin' around, I prefer the HTG, but the choice is very subjective.

If the long range hunting includes a lot of movement on foot, HTG would be my pick. If it is mostly hunting from static positions, and motorized movement, I'd opt the A3.