T'Mater
Ya, that's exactly why I'm never impressed, or even believe a manufactures propaganda. They will always be one sided on how they present their information. You'll notice even in the sure-to-grow video they made a point of listing the pro's but failed to even mention any cons. They simply make it sound like their product is the best product ever and for every system there is, as well as in every situation. But that's nothing new, all company's do that, so you just need to use common scene, and take what they say with a grain of salt. That said, that dosen't mean that all info from manufactures is bogus, just that they want to put there best foot forward without saying anything that might be negative about their products. You need to figure out the negative yourself. That's legitimate company's, there are some that will even knowingly just lie about their claims (not saying Sure-to-grow is lying about anything).
But in the third video about the NFT system they don't really show much with relation to weather the media is sitting in the flow of water. But it still sure looks like it to me. I see the cubes are sized to fit commercial NFT gully lids, but they aren't supported by anything. And the cubes look to be long enough to reach the bottom of the gully's. But even if they are slightly shorter, moving the lid around and/or the weight of the plant will eventually push it all the way down through the hole (as looks like many are). So it sure looks like it's meant to be subjected to water 24/7. But even if it is slightly above the water level, the roots have a very short trip to the water, and the roots will wick up moisture to the growing media (once they have grown through).
I understand the STG product is more like a open cell synthetic (similar to a sponge) that you can manhandle and it will come back to the original shape (like a sponge). But I have never come across a situation where I would need to do so much manhandling as they did in the video. Even if you did need to, you would do extensive damage to the plants roots and wouldn't have any plants left anyway after that (regardless of growing media).
When I say the STG's is high cost, I'm mostly making comparison's to other alternatives. I'm at the point where I want to grow large plants, as well as a large number of them. That's a big difference than just a few cubes, and they don't really give discounts for volume. Same thing with
nutrients. The GH Flora series nutrients are great, but it gets really expensive if you have more than a few plants.
I cant give you exact prices for the STG product I've seen because I rarely do price comparisons on it (if ever). But every time I have seen it, I wind up saying to myself, price wise that's no better than rockwool in price (and often more). But I'm more interested in the "fill" rather than the cubes because most of my containers are buckets and/or baskets. But the last time I looked it would cost more than $10 to fill a 5 gal bucket with the STG product. Same with rockwool. So they are both to expensive for me to consider. If you are only filling one 5 gallon bucket it might be OK for a test to see if the plant will grow. But when you are wanting to fill 30-40 buckets, that price just becomes out of the question, and simply time to look for alternatives.
Right now my growing media of choice is coco chips, I like it's moisture retention properties, as well as it's aeration capability's. I can completely fill three 5 gal buckets with $10 worth. Four when I add rock to the bottom of the buckets for weight and excellent drainage. $10 worth of coco chip will fill over 200 three inch baskets. So when I say too expensive, I'm comparing it to other alternatives, and quantities I want/need. But when you are wanting to fill 30-40 buckets with growing media, coco chips can becomes expensive too. So I'm looking into using pine shavings, and looking for regular suppliers.
P.S.
However if you are just needing a small 1 inch or so cube for each plant like for the NFT lettice, the cost for the sure-to-grow product is reasonable. But it's still in my nature to find alternatives if I can. I have even tried using cotton balls as seed starters. That works as long as you control moisture very well. The cotton wicks up moisture like nobody's business, but dries out fairly quickly. So water to air ratio with cotton is difficult to control. But it was priced right.