Venus Pax wrote:I don't really like the idea of horizontal shoulder holsters either. Why is switching to a vertical a big deal?
ETA: I've been married for ten years. That's not as long as many here, but long enough to know that two people don't always agree. I usually ask myself: "Is this worth standing my ground over?" If it is, I'll stick to my guns (pardon the pun

). If it's not, I'll give. I've found that it works.
Fair question.
First, I would be severely limited in the number of quality holsters I would be able to look at. There is a plethora of cheap nylon vertical holsters available, but they all appear to be a total waste of money.
Here are few I would be able to choose from (including one of the cheap ones).
http://www.ccwsupply.biz/RossM43AShould ... PHOTO1.gif
http://www.ccwsupply.biz/GalcoVerticalS ... PHOTO1.gif
http://www.ccwsupply.biz/RossM43Vertica ... PHOTO1.gif
http://www.copsplus.com/products/large/um-7501-1.jpg
Basically, vertical shoulder holsters require a much different draw stroke than a horizontal one. If you want to see the much touted "Slow and awkward draw" this is the group they are talking about.
Most vertical rigs require an upward movement to withdraw the weapon, this is opposite of where I want to go with my draw stroke, it also means wearing a "tie down" which I do not like. With a horizontal rig...you simply snap the weapon downward (and out) for a very fast and safe presentation. Even those that allow you to rotate the weapon adds time to the draw and still covers you on weak hand draws.
Most vertical rigs have no thumb-break that goes between the hammer and firing pin (or behind it on LDA's) which adds yet another level of safety. Instead they have a retaining strap that must be manipulated by the index finger. There are few that have a spring steel retainer that you "pull through" (not the best retention device).
Weak hand draw with a horizontal rig is easily accomplished and does not "cover" you in the process. Vertical rigs (most) would be difficult to do this from.
Vertical rigs require that get your thumb between your body and the weapon in order to get a good grip (easily muffed), they also require you to bend the wrist/hand downward in order to grip the weapon. This serves to shorten the arm causing me to reach further across my body...aggravating an already sore shoulder and presents ANY shooter with an initially "weak" grip.
I looked at both versions (Horizontal and Vertical) before choosing the one I did many years ago. Horizontal looked like the clear winner to me then as now.
Also, If we are to be intellectually honest about this
...."Horizontal" carry of any fashion should be a concern. I can see this taking in "purse carry", or even having a weapon laying on the seat of a car.. etc.
A little off subject....but those who carry in a "belly band" are almost always covering themselves just as soon as they sit down. Same with most IWB's.
Just something to think about.