I can’t speak for Canon, but I know that the Nikon speedlights can sync with your camera or you can use TTL metering when they’re off the camera however I never use them this way. I sync it with my pocket wizard and control the light manually as I would with my regular strobe heads. That way I have complete control of my light instead of letting the camera “guess” for me, which is common and easy to do when you’re working with speedlights. It’s important to me to always have control of my lights. Always. Your lighting is what conveys your vision and your vision is what ultimately speaks through your photographs. I use speedlights sparingly and carefully to enhance the overall lighting on my shoots. And for this, I think they do indeed get the job done!