I've used a Predator IV pendulum for the past 5 years and won't ever use another site for my treestand hunting. Once it was sighted in all I had to do was put the pin on the spot I wanted to hit and the arrow went there. In those 5 years I haven't missed a deer shooting out of any height treestand.
What you say about being accurate out to 35-40 yards may be true for a very fast bow, but every bow will have a different accurate and effective range depending on the bow's speed. I have my sight on a new bow now, but my previous bow was dead on at any distance between 5 and 25 yards. The statement that was made about pendulums not being able to shoot uphill is false for a Pred.IV. The sight has a pendulum stop that prevents it from swinging backwards so on a uphill shot its identical to any fixed pin sight.
Using a pendulum and hitting your target is in no way, shape, or form luck. Its about eliminating variables. You don't have to worry about what pin to use for what range, and you need not even woory about range as long as you know the deer is within your accurate distance.