HPS/MH working together?

I'm in the early stages of building a new room. I currently have 1 150w HPS and my question is should i get another 150w HPS or a 150w MH, I am going to run these lights together from veg through flower. Will it be more productive to run all HPS or have HPS/MH together?

i say get another hps, and then just get conversion bulbs, that way you can run 300w of mh during veg and 300w of hps during flower, just my opinion.