I have a different opinion of the I series shafts. I played with an I-3 for about a year, and also played a few racks with an I-2. Prior to this, I had been playing with a 314-1 and then a Z-1 for several years. I had to make no aiming changes with the I-3. In other words, the deflection on the I-3 was comparable to the Z-1 and the I-2 about the 314-1.
I have since gone back to the predator products when their Z-2 and 314-2 came out. But I was not unhappy with the I-3. I thought they were about equivalent and decided just to stick with the predator brand.
Let me also state that I am a player that can't play at all with house cues or normal cues. They have to be low deflection. I know some players say there is not much difference to THEM, but to ME it is like night and day.
Also as far as speed Im a C+ to B- player (4 to 5 ball ghost).