Just because some people fail at a method does not mean it can't be done! Just think what the world would be like if every time someone pronounced they had tried something and it didn't work, the rest of us simply agreed and moved on.
As an example, about 25 years ago, I had a very famous PhD, author, and self proclaimed "Expert" in all things hydroponic in one of my commercial greenhouses telling me that they had tried growing tomatoes and cucumbers in an NFT system in the "lab" and it simply didn't work and that he published that information in his last book. While he was telling me this, he was eating a tomato off of one of over 1000 plants I had growing in a large scale NFT system. My response to him was simply "good thing I didn't read your book before I built this greenhouse then".
I have grown countless different types of plants in NFT systems over the last 30 years without having DO in the root system be a problem. I still have peppers, melons, basil, lettuce, and tomatoes growing out of vinyl rain gutters on the side wall of my greenhouse and they produce enough each year to cover my operating expenses for the entire building.
There is a higher risk of problems with NFT in that if a pump quits or reservoir runs dry and no one is there at the time, you stand a good chance on loosing all your plants but there are also backup systems or alarms that can easily be built into the system to keep from having major disasters.
