I have three and feel that they are about the best available...
Have one on my Marlin 1895GS in 45-70, one on my 14" barreled Rem 870 12 gauge and another on my 21" barreled Rem 700 LSS in 375RUM.
I have all 3 guns setup with scopes, when I want the XS ghost ring on I just pop the scope off and install the rear sight.
45-70 = 6 350gr A-Frames @ 2100fps into 6" @ 150 yards.
375RUM = 3 350gr TSX @ 2450fps into cloverleaf @ 50 yards here is a pic the lower hole is from sighting in my 14" T/C Contender carbine in 45 Colt.
