If you're so close to your attacker that you're just point-shooting, any slight variance in POI due to the grip will certainly be irrelevant. If you're using the sights, then the only thing that will matter will be the sight picture, which is totally independent of the grip. The bottom line is that if you have the correct sight picture when the round goes off, you will hit the target, whether the grip you're using is high, low, or two fingered, or it's dangling from your thumb.
Myself, I really DON'T LIKE the grip angle or feel of the Ruger Single Action revolvers, ANY SA revolver for that matter. I own two, and just plain don't like them compared to DA revolvers. That said, I have no issue shooting them accurately, the same as all my other guns.
None of the grip angles of autos have the extreme difference that the SA vs DA revolvers have.
It's very easy to go to the range, shoot a mag out of your buddy's gun, and instantly say, 'I didn't shoot as well with his Glock, CZ, Sig, whatever, as I did with my whatever'. This is truly not giving the gun you were trying out a chance. When I shot and reviewed the SR9, I borrowed a friend's gun and shot close to 100 rounds out of it before I stated my opinions.
Basically what I'm saying is that you need to do a LOT more than handle a gun in a store or blow through a mag in your friend's gun to make an intelligent decision on a gun. Think of how many times you've bought a new gun, and it took 4 or 5 mags worth to learn how to shoot it well.
With all the millions of Glocks sold each year, their grip cannot be as 'difficult' as many glock-haters state. If you can't make a Glock work for you, I'd think it's more because you don't WANT it to work for you, rather than that it WON'T work for you after a little serious and dedicated practice. That goes for ANY gun, not just Glocks.
I've found a few guns with grips I didn't care for, mostly SA revolvers, but it never stopped me from shooting them well. The same goes for autos. I've heard people say 'I can't shoot 1911's well'. Well, if you can't shoot a good 1911 well, you'd better give up shooting, because there is no other gun on the earth that's easier to shoot well than a quality 1911.
Shooting a gun well and being proficient at it is far more a result of practice, than initial impression of whether the gun's 'grip angle' is acceptable to you. Guns don't 'shoot low or high' because of grip. If a gun doesn't shoot to POA, then you're either using an incorrect sight picture, or the sights need adjustment. If a supposedly 'properly sighted in' gun doesn't hit POA, then it's not sighted in ... period. I've actually had people who thought they knew all about guns, say ... sight picture ??? what do you mean by that ??? Geesh ....
Pick a few guns that you like and that have the features and capacity you need, shoot them a good amount if you can, buy the gun, and then learn to shoot it and be proficient at it.
REV