You bring up some good points but with "if's" and "probabilities" and add an accurate statement of "What the range of travel is of those cheap shocks is compared to others such as Hagons I have no idea". He made a blanket statement based on the shaft being shorter that it would be stiffer. The range of travel on a shock is determined inside the body, not by the length of the shaft. If you shorten the shaft and add a 2" longer mounting assembly at the end the overall length remains the same and doesn't necessarily shorten the travel of the shock. A shock may have a 6" long shaft and only use 4", or 66% of the length for travel while a shock with a 5 inch shaft and an inch longer mounting assembly may still use 4" of travel or 80% of the shaft length. Now lets go to the spring. If the long shaft shock uses a single rate 200lb spring it remains at 200lbs the length of it's travel . If the shock is shorter with a progressive rate spring of , lets say, 200/225/250, the shock will not be a stiffer ride until you are about to bottom the shock out and it start to compress the stiffer rate. So to look at that shock and make a statement that it is stiffer because the shaft is shorter is just not an accurate statement.
The OP wanted to know if anyone has used these and so far the answer is no. My opinion, for what little is it worth with over 30 years of competitive driving/riding, is that these seem to be a better quality than the cheap Chinese shocks we read so many negative things about. In the meantime I am still waiting for TEC to tell me where they are manufactured.