With my SDC, I use the Deteknix wireless headphones from Phase Technical.
They have inbuilt batteries and will run all day on a single charge. There is no apparent 'delay' in signal.
Their great upside...no bloody cords that want to rip the phones off your head the minute you put down the SDC and start to dig.
I have NOT tried the Minelab Prosonic so I cant do a comparison.
With headphones .....there appear to be some who push the 'high impedance' (150 ohms) headphones as being the 'best'...and others say 'ohms don't matter'.
Others say..get rid of phones and use BZ Boosters...or equivalent and small speakers.
For all this 'stuff' there is no equivalent of a Choice Magazine that does all the comparative tests for you and tells you (based on several comparable criteria) what are the best options...either ....headphones, speakers, boosters, etc.
The next step is to be cashed up......to go out and buy all the various options, and find out what suits you best. No many can afford that approach...given a set of headphones is $120+++.
What's the answer.... it depends on each individual.
If you know your hearing is OK (or after a hearing test)...work out whether your preference is headphones or a speaker system.....once that decision is made...Research and then invest and maximise the investment by trying to get the best out of equipment and not easily giving up.
We are probably all impatient to get to the perfect outcome...the reality is...life ain't usually that easy