DiPricol all the way, several different models/ styles to choose from, and are very tough, and accurate. I have installed many, many, sets of these on customers trucks, and have then on mine, never one complaint. They also make 1/4 NPT for your existing hole. The way I understand it, DiPricol's are facory gauges on Caterpillar heavy equipment, thats all I needed to know.
Isspro's are the cheapest gauges I've ever seen, to many unnessesary boxes/wires, and have installed some, when pulled out the the package, wires were pulled out of the various boxes, IMO, they are a sorry excuse for a gauge.
Later, Rob