I don't think the pcs will cut down the shimmer from the halides. The shimmer effect is frequently more a product of water movement- so you can direct a powerhead to disturb the water surface to get more shimmer.
I have the Hamilton 175W 10K and 55W 7100K combo and the shimmering effect is still there. My lights are about 10 inches off the surface! Go for it. What's your depth?
I have 2x96watts pc's on my 90 gal reef. Is that enough lighting to raise any kind of coral? I was considering upgrading to metal halides, but I've only had my tank running for 7 months. Therefore, it wasn't too long ago that I bought the pc's. If I were to upgrade, would I just add the mh's to the pc's and have both running or would the mh's replace the pc's?
Shimering effect is caused by a "point light source" not by intensity and not solely by water movement. You need both water movement AND a point light source to get the shimer.
MH light is strictly a point source, so if you have ripples on the surface, you will have shimer. PC is a long "bar" of light, so if you have ripples you still won't get much of a shimer compared to MH.
I LOVE my MH. I wouldn't do a reef without them. Flourescent lights are great for supplemental lighting like actinic, but for the sheer beauty and life-likeness of MH, they are the way to go.