It's noticeable compared to the VX3i, hard to make a direct comparison given the power range/objective size difference.
That being said, ive never felt ive needed more than my vx3i. Get it if your in the market for a vx3 or want slightly better glass. I probably wouldn't recommend replacing your current vx3i to get this one if price is a factor. It wasn't for me so I'll be replacing all my vx3i. I also like CDS and Zerolock so it was a no brainer for me.