I believe the reason the tip on the Ani saber doesn't light up is because they're using 2 separate technologies to light up: Ani's is using EL paper around the inside edge of the tube to light up while the Vader saber uses LEDs at the center of the core with the white inside edge of the tube simply being for diffusion. The different technologies may be why the blades are a different length too, but this could be the way it's mounted to the shroud/emitter.

Also, the Ani saber hilt is WAY too big, the actual prop is one of the smallest sabers ever (not counting the dinky ones for Yoda & the Younglings), so you might want to take that into account when comparing them. Vader's FX saber hilt is much closer to the original prop's size, but that prop was a big flashgun whereas the Ani one was not a flashgun at all.