I've bought more boots from Sierra Trading Posts than anywhere else. At any given time, I've always had at least one pair of Alico Boots in service for the last 25 years. I currently wear their Mountain Hunter, which is insulated. I have a pair of their Guide boots, that's a bit too big, and I've worn out multiple pairs of Summit and Tahoe. I also have a pair of Gronell Burmas w/ Outdry. I don't know if you can get them in the US anymore, but they are excellent boots.
Alico Mountain Hunter
Alico Guide
Gronell Burma MSR