I would not buy it.
1) "*Peep" sights/ghost ring sights (like on the AR15, etc) work because your eye is close to the rear sight and the rear sight "ghosts" out as you focus on the front sight. With the pistol at full extension, your eye is too far away from the rear ring to "ghost" it and you end up focusing on the rear sight as opposed to the front. When that happens, it becomes very difficult to make hits.
2) From their site: "HexSite® sight's graduated-profile will not snag clothing or holsters, nor will it hinder concealed carry." These guys have NO concept of fighting with a handgun. "no-snag" sights "no-snag" the wrong way. You WANT the rear sight to snag if you have to do a 1-handed slide manipulation and rack the slide off a belt, etc. Graduated profile sights like these and Novaks look super cool and make 1-handed reloads, etc. VERY difficult.
Why would you need to do a 1-handed reload? Well, good dudes get hurt in fights too.
I'm a XS Big Dot fanboy but Meprolights or Trijicons are fine too if you want a more traditional sight.
Take care and stay safe,
Mike