I have 2 Wally world turkey fryer burnes and they seem fine so far. The difference between the low and high pressure systems is BTU output capability. High pressure @ 02 around 30 PSI will get you 180,000 plus BTU, Low pressure will get you a bit less. High BTU's heat water faster, but also increase the risk of scorching you mash and extracts if you do not stir them completely in when you add them. My system is low pressure since I am in no rush to get a quick boil. I tend to believe a slower build to temp is better for flavor and efficiency, but I could be way wrong too. I dont have any empirical evidence to suport that theory so take it at face value. There are a lot of high dollar burners available and in a more advanced setting they may have attributes that would make them more neccessary, but for the hobby garage brewer a little slower is usually a good thing anyway. My propane tanks last a good long while too. I think the high pressure systems waste a lot of gas because they are so aggresive when on full tilt. Water will only boil so fast and attempting to speed it up usually creates other issues like boil overs, scorching, caramelization, and excess tannin extraction which adverly affect the end result. This is just my thoughts, YMMV, so don't base 100% of your decision on the answer of one fairly still new to brewing. Have a great day
Wheelchair Bob