RE: 5 pin or 7 pin sight?
I currently have the spot hogg hunter 5 pin on both my bows. I like it very much. I won't be regularly shooting at distances that require a 6 or 7 pin so that is why the 5 pin. When hunting season starts again I will actually be removing the 4 and 5 pin. During hunting season my max practice range is 35 yards (my hunting range is 25) so I won't really need the other 2 pins.
With all of that said, decide what ranges you will be shooting and what pin spacings you want(10 or 15 yards) and get the sight with the number of pins you will need.