I fell in love with Merrell hiking shoes/boots about 17 years ago and for a few years could get them in the same size (US13) with a virtually identical fit and near identical feel. Then I think the company changed hands and nearly every Merrell shoe/boot I tried had as above very variable fit and sizing for about 6-7 years, then I tried them again and they started fitting again, still at 13US, like they did before. Not sure what happened but have been happy with my Merrells ever since, so I typically try to stick to them if I have to mail order something.

Aftermarket inserts can also make a big difference too. If a shoe fits a little loose I can buy a Montrail insert in size 14 which brings them down to my usual 13 fit.