A good MH will produce high PAR spread over a 24x24 area, (some do more) this is dependent on the bulb, ballast and reflector. Not all bulbs put out the same, a poor performing bulb such as the XM 15k will not put out the same PAR as a 20K Radium and none do as much a 6500k Iwasaki. The difference between those 3 bulbs is very high. If you compare all 250 watt bulbs on Sanjay's site, the range in PAR is from 189 to 33, all of those are 250 watt bulbs. So which setup is the LED fixture equivalent to? For the LED mfg to make that claim is simply absurd because the range is so great. Even the lowest PAR bulb tested would have better spread than the LED fixtures currently on the market.
You really cannot compare a PC fixture to MH or LED. The difference is PC is that it is not point source and is very inefficient at putting light into the tank. I would expect any LED fixture to outperform the PC fixture. It looked "dirty" because it isn't the same type of light but in reality light isn't dirty.
I suspect your tank will do very well with those fixtures, coming from PC's almost anything will be better.