I fitted alloy push rods, supplied by Draganfly, 4000 miles ago and have not needed to adjust the clearances yet, the other post referred to above mentioned there was a known problem with alloy rods having an incorrect radius on the ends which caused them to stick in the rockers, Ive seen those duff rods myself, a friend showed me some he had trouble with, the difference between good and bad radius is not easily seen but might be the cause of the poor reputation of alloy rods?
Ive been told most parts are made by one uk company (yes I do know their name), who only supplies wholesale, hence when they stuff up all suppliers buying from them tend to have the same quality issues, and some suppliers (grrrrr) keep on selling known duff parts until the stock is used up, despite knowing of the issues - the reason being the uk manufacturer will not take the duff parts back under "warranty" that they manufacture.