I love the guy. I wanna spend just ONE week with him. But here is what got him in so much trouble a few months back with the ATF.
http://totalfratmove.com/dan-bilzerians-hilariously-apathetic-government-mandated-psa-has-been-released/
The hd are more precision shooting sights if you wanna call it that. I like the i dots. Very easy and fast target acquisition. But I also like the U shape rear sight of the HD sights. Both have the big colored dot up front with the illuminated paint. Just personal preference if you were gonna...
Tfo's are awesome! Have them on my 17 and 19. On my other 19, I have the trijicon hd sights. I have the pro I dot on my shield which are great for SD. I really do like the tfo's the best but to each his own.