MH vs HPS yields

Is there an actual difference in yields between using MH instead of HPS lights for flowering. I am debating the wether or not it is worth purchasing an HPS system. I have a MH right now for my veg state. I know that HPS is supposed to have more blue spectrum, but from the diagrams I've seen HPS and MH look to have almost identicle spectrums of light. Has anyone tried to flower with MH and if so what were the results?

As far as I know, HPS tends to output more lumens per watt than MH. Though more lumens doesn't necessarily mean more photosynthesis spectrum lumens so I don't know. I'm unfamiliar... I had read that HPS tends to give slightly but not drastically greater yield over MH in flowering, but this was just a few anecdotal reports online and could be totally wrong.

MH pumps out 20 or so less lumens per watt of light. So yes that will effect your yields. However you can still grow some bomb ass weed using MH. If you're limited on cash and can only use 1 type of bulb then buy a HPS. If all you have right now is the MH and can't buy a HPS then by all means use the MH. Like I said you'll still get bomb ass results.