I am a huge fan of the finger on the trigger guard. When I first started shooting this sport I used a conventional grip because that is how everyone told me you were supposed to grip the gun. But that grip was not comfortable to me and in fact my non shooting hand index finger actually got in the way of my trigger finger. Eventually I finally saw a video of Eric Grauffel shooting and him kicking everyone's ass using the grip that you are asking about. So I started practicing drawing and shooting with this grip. It hardly took any time to get used to simply because this was the most comfortable way for me to grip the gun. Now I do believe that the biggest factor in using this grip is strictly determined by your hand size. If you have smaller hands it is going to be tougher to use this grip than if you have larger hands, but the key to any grip or technique is practicing it until it becomes second nature. Don't believe all the bullshit that you hear about that one finger causing you to pull to the left or low or in any other direction. If you are pulling off when then shot breaks that is a flinch or poor trigger control. You hear all kinds of BS these days about how much pressure to apply with each hand 60% this hand, 40%with that hand, blah blah blah!! That's all horse crap, if your gun is sight in correctly and you line up your sights and make a clean trigger press without disrupting the sights regardless of how much pressure you put where on the pistol, the bullet will hit where you are aiming. The whole point that I am trying to make is determine what works best for you and what fits your body type the best and then practice like hell until you reach your shooting goals.