I've had the AB400s since 2000 and I've never missed a shot with them. They work great in my fairly small studio and they work great on location at shows. They also recycle in approximately 1 second which really helps catch those ooops/got it moments with dogs and tongues. With my 400s, I'm at F8 and 1/250 at ISO 200 so I really don't need more power. I suppose if I were using them a lot outdoors, I'd want more juice but I don't. Just my 2 cents.

Jim