They may have similar parts, but not similar engineering... and I will bet that the Mac will still be cheaper than the sum total of the cost of the equivalent parts. This is what Mossberg is referring to... superior hardware.
Apple uses the same panels for there LCD's as Dell. Most of there components are rebranded by them. The motherboards for Macs are made by intel, and you can readily find the equivelant to them for PC'sm exccept some changes are made for Apple like the memory. The video cards are the exact same ones you can buy for PC's, which by the way you as far as I can tell Apple always seems to be a bit behind in having the best video cards available for there desktop PC's and laptops. Like I said the key difference isnt the hardware per se, but the small proprietary differences like the bios and small changes made to the hardware.
But it's very nice hardware, for a fair price.
If what you want anyway closely matches an available Mac hardware model, that may well be your best choice. But if you have other specific needs, then usually you can get a better fit in the commodity PC hardware space.
If price is a key selection criteria, that "better fit" can include a lower price, in which case your hardware might not be as nice as Mac hardware, but it may meet your needs just as well, if not better, for less money.
For a couple of my relatives who just need simple documents, email and web, I build systems for a few hundred dollars, plus monitor and printer. I could do that with a Mac Mini, but it would cost two to three hundred more.
For my teenage son and his friends, I build gaming systems for perhaps a thousand to fifteen hundred dollars each. I could do that with a Mac Pro, booted into Windows (serious games are exclusively Windows), for perhaps an extra thousand dollars.
The same applies on the high end -- for my day job, I work on ten thousand to ten million dollar systems, built mostly from commodity PC hardware ... very select, very leading edge, industrial strength, commodity hardware. In another window, I just logged off a system with 2048 CPUs and 4 terabytes of memory (RAM, not disk). It was running a single Linux boot, not a cluster. Apple is not one of the vendors we deal with.