I have both, . . . I prefer the horizontal carry, . . . even though my rig actually carries it pointing upward behind me (it is more comfortable for me that way) as opposed to an absolute "horizontal" plane.
It is my favorite carry, . . . especially if I have to drive any appreciable distance.
I wear it under a vest, . . . under a coat, . . . and sometimes: under a snap front, short sleeve shirt (summer only). Never been made yet.
The best part of it is that it allows me to carry two mags on the off side to help balance it, . . . works great.
Oh, yeah, . . . I carry a full size GI, steel, 1911 w/8 rd mags.
Concealability is no problem unless you want to wear a wife beater or a silk like shirt, . . . it will print through the silk. It can be presented almost as fast as a hip carry, . . . but you also have to practice more with it.
My one fault with it, . . . you really cannot run flat out with either of mine, . . . something gets to bouncing and becomes bothersome with either of them. That does not happen with my IWB rig.
May God bless,
Dwight