I've never used them on boar but have used a holographic sight a lot. They are good but sometimes it can be hard to find the red dot if you haven't got your eye square behind the sight correctly. If your off to the side too much the hologram won't be seen correctly. They are good for rapidly aquiring a target because you know if the hologram is on target then that's where the bullet is going, Unlike an iron sight if your not lined up right then you don't have the correct point of aim, even if you haven't got an ideal stance or firing position.*
Another plus is you can keep both eyes open giving you more vision than with your eyes glued to the scope and cross hairs, which could be a bonus for driven boar. I tend to notice the point of aim moving with a holographic sight, because of breathing etc more so than with an iron sight which I guess is the same as a standard scope and x hairs, you need to trust the zero and your shooting skills. Hope that helps. *
John *