I have used tons of MH, and I have always come back to PC for plants. The MH does not have the wide range of spectrum output you can get in PC.
For example, I tried 2x175W MH w/ 2x48" NO flos. I tried pink flo with 6500K's, 5500K's with white flos. Just about every single combo possible. Never got the tank to look HALF as nice CRI wise and visually pleasing as 2x65W 6700K & 2x65W 9325K. Not to mention the heat MH give off. I also find now on my SW tank, I prefer PC as well. I can finely tune the amoung of blue & white much better with 10ks, 50/50s & actinics then you can supplementing MH with actinic. In some circumstances you need MH, but for my purposes and the purposes of many, you can replace 250W MH with PC easily.
For example, I tried 2x175W MH w/ 2x48" NO flos. I tried pink flo with 6500K's, 5500K's with white flos. Just about every single combo possible. Never got the tank to look HALF as nice CRI wise and visually pleasing as 2x65W 6700K & 2x65W 9325K. Not to mention the heat MH give off. I also find now on my SW tank, I prefer PC as well. I can finely tune the amoung of blue & white much better with 10ks, 50/50s & actinics then you can supplementing MH with actinic. In some circumstances you need MH, but for my purposes and the purposes of many, you can replace 250W MH with PC easily.