Online magazine articles at circuitcellar.com are apparently restricted to those having a subscription. I think.The thrust of the article is many Arduino boards use the miniscule SOT-223 v.regsand these will overheat rather nastily if dissipating more than about 0.5 Watt. Of course, this has been commented on in numerous threads on this forum.The author's choice of workaround is to use a TO-220 7808 in the Vin line to reducedissipation in the SOT-223 device.The other criticism is that the "tuning fork" style contacts used in Arduino female header pins do not make very good contact for current driving situations, especiallywhen inserting circular pins.
Well any modern linear regulators have internal auto shutdown protection if they overheat or too much current is drawn, so I think more is made of regulator heat then really needs to.
And once you commit to external regulators, using linear regulators in this day of very inexpensive Asian switch mode voltage regulators makes little sense to me.
Those arduino shield connectors work great if used as they were designed, which is male .1" square header pins, not random round wires.
Practically speaking, he computes that, for Vin = 12V, you can draw only a miniscule70 mA off the SOT-223 v.reg before it overheats beyond what he's comfortable with.
It re-affirmed to me that using an external, well-regulated power supply for my home-grown boards is a valid design choice
Small switch mode external power supplies are available for about $5 these days
Not sure what approvals mean anymore in an era where such approvals are easy to fake. Just take apple 'cube' power supplies as an example. Many fakes are good enough to fool even experienced buyers unless you know what to look for and test the unit. For that reason, the reseller is actually more important than ever.
Most of the 'reputable' CN houses will and do warn on the Ebay page that when using the device at max rating that more heat-sinking is required.