If you try to drain the last minute of daylight out of a hunt dots have there drawback. However remember the dot will be bigger at 3x than 9x so depending on the size of the dot you have some wiggle room at the lower powers. In an old Leupold catalog I have they list the vxII 3x9 with Leupold dot covering 3.6in at 3x and 1.4in at 9x. They will fade out the last 15min of shooting light depending on background and if you have snow or not. I have yet to have it be a problem, but if the game has beat me up till that last 15min they are going to have to be close for me to shoot anyway, so I don't worry about it.
The dot is probably my all time favorite reticle and I have a scope going back to Leupold to have one put in.