^as above^
Much bigotry around this topic and while it may have been true that ½" was better when we all used heatercores and pond pumps with simple maze-style blocks, it has since been proved that with modern blocks, pumps and radiators there is little measurable difference between tubing sizes. I like to use 7/16" over ½" barbs because you don't need clips and that makes it look neat and tidy. (Slightly never-wracking the first time but after that, it's all safe enough.)