Disclosure I was the GM for a boot manufacturer the companies I will mention I was not involved with. The stiffness ( spine) is created by two things the footbed and some will have a longitudinal plastic ( some it’s even metal ) spine. The spine is important for two reasons. It’s reduces the horizontal flex to protect your ankle and it add much to the feel when walking ( toe to heel ). If it’s too stiff it’s uncomfortable, too soft you lose protection. Look for a boot with replacement foot beds if possible as they wear out over time.
The tread patterns don’t make much difference they are pretty good. They do a couple things allow traction and drainage of water and mud from the boot while stepping. Some are deeper than others and it’s based a lot on terrain. Deep treads work a bit better in lots of mud and water. They can feel clunky and clumsy though. So look at your area.
Insulation is good if needed. I like two pairs of boots. Warm weather can cold. Stay away from Gore-Tex. The problem with it is while it will keep your feet dry all boots are permeable so just take more time . Water will get into them unless they are rubber. When Gore-Tex gets wet it has a very long time to dry out. Days in fact. The moisture with quickly breakdown your skin. Insulation should come from your wool socks not the boot. The materials are to keep your feet dry.
Thinsulate is a much needed improvement as it has a waterproof layer that the older Gore-Tex. Some of the cheaper boots with use the older material.
Steel toe cups for protection unless your using them on the job avoid. The metal will get hot or cold quickly , add weight. They have some boots that have a polymer spine toe and heel cups that are very nice and mostly seen in mountaineering boots ( Scarpa, La Sportiva).
How tall of a boot? It is marginally better to get the 11” boot for lower leg stabilization and protection vs the 8”. I have no strong feelings as long as it covers and supports your ankle well it should be fine.
The well known boots are Rocky, Salomon , Danner, Lowa and Merrell. Some have military contracts ( Rocky and Danner ) and you maybe partial to them as you know how they preform. A good boot is 150 and up and will last a long time as they can be resoled as well
There are a lot of smaller manufacturers and as long as they have all the features you need they should be fine as well.
