Both displays have pros and cons.
What size are you looking at and what gpu do you have now?
Generally speaking, VA's offer deep blacks and good color with somewhat narrower viewing angles. Some "smearing" can occur with fast motion.
IPS panels have very good colors, a wider viewing angle but poor blacks compared to a VA. IPS panels can also suffer from "glow".
This tends to come down to what your eyes see. Do you have a Best Buy or similar store near you? First thing I recommend is to go look at different displays and see what your eyes prefer.
I use an IPS panel. Wish it had better blacks but the image is crsip and smooth for FPS shooters.