Yes, some of this is BS but there is some truth, expensive truth, but still truth there.
I have 2 of these, a 1K that was up on its 20 ft tower for a while and in a large gust I did see 800 watts or so. It is currently on the ground waiting for a much taller and stronger tower so time will tell. The other is a 200 watt that a friend bought and I recieved from his estate after he past and is still in my shop, again they need real towers. For instanse the 200 watt came with 12" pound in pegs for the guy anchors.
The alternators themselves don't look to be all that bad and include slip rings if that matters to you. The blades arn't the best but others have found ways of making them work better. Personally, I wouldn't buy one of these again, to much work needed to make them useable.