The thing they agree on
Both boots are Goodyear welted. That single shared fact puts them in the same category and separates them both from the cemented and direct-attach boots that dominate their price brackets. When the sole on either of these wears through, a cobbler can replace it without touching the upper.
So the comparison is not "repairable versus disposable". It is "how long does the upper last, and who will do the repair".
Leather: the honest difference
Red Wing's Amber Harness is a thick, oil-tanned full-grain hide from its own tannery. It creases shallowly and slowly, takes conditioner deeply, and the creasing improves the way it looks rather than degrading it. Thursday's full-grain is thinner. It creases sooner and deeper, and after three years the two boots look noticeably different at the vamp.
That is where the 150-dollar gap went. Not into the welt - both have one. Into hide thickness, tannery, and the labour of a domestic factory.
Repair path: Red Wing's clear win
Red Wing operates its own repair shop at the Minnesota factory, and its stores take resoles with original parts. Thursday does not run a repair program, which means your resole goes to an independent cobbler with a generic sole unit.
For most people an independent cobbler is perfectly fine and often cheaper. For someone who wants the boot to come back looking like it did, the factory route is worth real money - and it only exists on one of these two.
Comfort and break-in
Thursday wins this decisively, and it is not close. The Captain is comfortable within a week. The Iron Ranger's double leather toe and flat Vibram 430 sole make the first month genuinely unpleasant - this is the most common complaint about the boot and it is a fair one.
If break-in is the thing putting you off the Red Wing, the Blacksmith is the better answer than switching brands: same welt, same factory, single leather toe, days rather than weeks.
Warranty: neither of them
Red Wing publishes twelve months against defects, original purchaser only, receipt required, with excessive or abusive wear excluded. We could find no published warranty terms for Thursday at all. Neither of these is a reason to buy either boot, and anyone telling you these are lifetime-warranted boots has not read the documents.
The verdict
Buy the Thursday Captain if this is your first welted boot, if you want to wear it with trousers as well as jeans, or if 350 dollars on footwear is a stretch. It is a genuinely repairable boot at a price where almost nothing else is, and that is a real achievement.
Buy the Red Wing Iron Ranger if you already know you like this kind of boot and you intend to keep it for fifteen years. The thicker hide and the factory repair path both pay off over that horizon, and neither pays off over three years.