A video demonstrating the differences of inheritance in Tribes Ascend.
Things to note that would have taken up too much text in the video.
Where the disc hits at 50%, is exactly half way between where it hits at 0, and where it hits at 100. Likewise, at 80% it hits 80% of the way in between.
What this means that for a shot with 50% inheritance, you actually have to aim twice. You have to figure out where to aim for 0, where to aim for 100, and then aim in the middle.
With a pure 100% inheritance that doesn't happen, you only have to worry about where the reticule will be.
Similarly with 80% and 50% you can see how the longer the disc travels, the greater the "trail" becomes. This is evident in when comparing the zoomed shots to the non-zoomed shots.
With 100%, there is no trail, and that remains a constant.
Also of note, yes 100% (or any non-0) value will make hitting a stationary target harder. But it will make hitting a moving target easier.
With 100%, the closer in speed you are to your target, the less you will have to lead any shots.