I've been using a pendulum sight for 4 or 5 years now and love it. Its an Impact archery "All Terrain" sight. It is a single pin pendulum for in the treestand or you can lock it down and has adjustable yardage markers on a slide for on the ground.
I shoot indoor targets, outdoor 3-D, and hunt all with one sight. A pendulum can increase your odds on deer, just practice with it from an elevated position, because like the other guy said it will probably shoot inch or 2 high in close, right on around 25yds and inch or two low at 30-32 yards.