Just about any trigger time is good. I've shot IDPA and it reinforces some bad habits, but it aint bad either. Self defense is much different than target shooting. I'm a strong advocate of point/instinctive shooting, but sights have a place also. My gun club is a great place to target shoot and sight in firearms, but doesn't lend itself to good self defense shooting. Consider yourself at the range target shooting, then consider youself at the ATM, opening your car door, going through your house in the dark... and having to use your firearm. Self defense is generally seven paces and less, and one handed. How many rooms in your house are more than 21 feet long. How many people get robbed at more than an arms length away. If you have to use a firearm for self defense you may have a flashlight in your other hand, car keys, wallet, debit card, phone with 91 dialed, around your kids or wife/husband, opening a door, turning on a light...
Here's a great drill. Put electrical tape over both sights. Holster the gun (this can be difficult with tape,) stand in front of a human type target at five yards. Put your none dominate hand up in a stop motion. Draw your firearm and shoot at the point of the target your looking at. Draw and fire draw and fire. Square yourself to the target, forget the weaver stance (we have eyes facing forward, we are predators, we face our threats and crouch slightly,) you will find yourself hitting what your looking at. My 2 cents.