There are 2 types of hackamore (kind of): traditional hackamore (reins attached to knot under the chin) and sidepull (reins attached to the sides like in usual bridle). First one indeed is great for stopping and not so good for turning, 2nd one is other way around. When I started my horses I used sidepull with wide leather nose. However it does NOT have a good stop in it. Personally I'd stay away from mechanical hackamores. They are harsh (yes, yes, yes it all depends on hands, but what's the point of using mechanical hackamore if the horse is controlled in say halter with reins attached).