I am one who uses the crosshair style, I have tried the dot but I could not get
used to it.
As Phil indicated it is easier to see the dot at times, and many folks are able to
locate it in the center circle easier then quartering the crosshair in the same circle.
You may have to try both to gauge what works best for yourself.
Spending time behind someone else's scope on practice day is a cheap way to get a good
feel for the differences.
DanO