I've heard this many times, but we've got 6 3.2 rangers here at work, 4 d4d hilux's, a 9 yo old base amarok and numerous other older bakkies, not a single one of these bakkies has given any issues. And these vehicles gets driven with zero mechanical sympathy, the only two stand outs was the the amarok that had rear diff issues (driven on tar with diff lock on) and 2 of the hilux's that had some maintenance done on them, non of them had broken down or given any issues worth noting. So my suggestion would to go test drive those on your list and buy the one you like the most. Chances are you won't have issues with any of them. This, and any brand can give you a lemon, even the mighty toyota.
I forgot about the Navara, this one had lots of issues, nice bakkie with high fuel consumption, I wouldn't buy it as a personal vehicle though.
yeah, a lot of noise about Ford with no personal experience to back it up...
Of course, there will be examples of mechanical failure out there, but that holds true for any brand.