Dorman products and D-Tech are the same .. the PMD is made by Flight Systems, inc, and is re-badged by various companies.
About all I can tell you with PMDs is that they ARE going to fail... sorry about the fatalism, but that's just the way I see it. If you get them properly-mounted, on a decent-sized heat sink, with a good harness, mounted OUT of the engine compartment, they will last much longer ... but even then, I expect them to fail eventually.
Stanadyne or D-Tech, order one from a vendor that will back up their product with a good warranty.
Leroy at PMD Cable is one of our vendors, and offers either a cheaper version (1-yr warranty) or more expensive (7-year Warranty, like what Bill Heath sells)
You can build 'em yourself for less, but you'll have to live with the fact that if/when you replace it, you will be on the hook for that cost again. Depends on how long you'll want to keep your truck, I guess.