I'm not a full blooded lefty, I do some things right handed so shooting right handed isn't too weird for me and I do OK at it. I feel I could easily make the switch if I set my mind to it.
Couple things however:
1. It's more natural for me to reach for my gun with my left hand.
2. I'm left eye dominant.
I realize these two things would be pretty simple to overcome with practice, but is it worth it?
Advantages:
1. Holsters are easier to find.
2. Almost all guns are right handed, if not ambidextrous.
Additional thought:
1. You don't need to change holsters often if you buy the right one(s) the first time.
2. In a time of stress, will training prevail over natural instinct?