In the time I worked at an auto parts place, I saw a lot of trailers in need of bearings, and not one was an HF trailer.
Most, in fact, were homebuilts welded together by old boys whose work was good, but not their maintenance practices. (well maintained bearings do not melt or explode

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I could take that to mean HF trailers are good, or aren't in much use in my area.
I tend to judge an item's quality by my own perception, taking other's opinions under advisement IF they have actual experience with the product or have at least LOOKED at it themselves.
I have the utmost respect for people who know their business, but sometimes a reputation is undeserved, or the rep is deserved but the holder of the rep changes.
Taurus handguns had a bad rep for a while, and a number of people, some of whom make their living knowing about guns, still say Taurus handguns are crap.
I own both a Taurus .38 snubby, and a S&W model 13, and while either of them is reliable the Taurus will keep reliably functioning after the Smith has given up.
The Taurus also has a fifteen pound trigger pull compared to the Smith's twelve, and the Smith is an older model, but the fact is, while Taurus once richly deserved their rep for badly made handguns, that time has passed, and the company now makes a quality product you can bet your life on, so long as you don't buy older models, yet there are experts out there who've not touched a Taurus in years and roundly castigate them still, with absolutely zero justification, and of course there are others who've heard this opinion and accept it as truth without ever having verified it for themselves.
I have no judgement of HF trailers, and will not until such time as I actually see one assembled.
I also have no business advising anyone how to build a TD, not having built or even planned one out myself, but I believe the act of building a HF trailer (or any trailer) into a TD would tend to reinforce the trailer and make it stronger, as that idea agrees with what I know (admittedly mostly in theory, though I have some experience building structures that backs this theory up) about structural rigidity and integrity, as long as the TD was attached to, not just built over, the chassis.
I absolutely would not use one for an off road trailer build, though, because I don't believe they are rigid enough for that kind of pounding.
I don't think anything built from channel is that rigid or strong.