Anything under 10 is considered good for gaming.
To be honest the manufacturers spec for response time means absolutely nothing. It is always qouted as GTG these days and at that point the manufacturer would select the grey level they perform best in. So for that particular shade of grey the monitor might be good but pretty much all monitors still have Black to Black response time of 12ms. So it doesn't really matter how good they can do for one particular grey tone.
Also IPS panels looks much more rich in terms of color than TN. I wouldn't let 3ms bother you.