That one has been tossed around a bunch of times over the years.
If you ask 100 growers, you'll get 50 that say yes, 50 that say no.
Hhahaahahaha, many, many studies have been done on this as well, with no conclusive results coming from the tests combined.
MH will give you better average growth in the vegetative cycle than HPS. When combined, the results fluctuate with the strain with some giving better growth, some not.
I use HPS for my entire grow, on all my grows except the Host plants for cloning. I use a 250 watt cfl setup for them.
