I've previously had many boots including Mongrel, Steel Blue, Oliver, and the most recent being the Magnum Precision Max. The Magnums and these Mack Boots are both not cheap, and i guess considered 'high end' boots so lets compared those two.
The Magnums were size US11 look great, hard wearing, tough, and light. When I first got them they took around 3 months to wear in, i didn't wear them everyday though. Interestingly i always found my feet aching in them but i coped. The waterproofing is unreal, and lasted 5 mins in water easily. I could walk through shallow creeks and puddles without fuss. The zipper came apart after 18 months. I had it replaced, but was never the same and dedatched again otherwise the boots had heaps of life left.
The Mack boots are size US9 and still have room to move! The sizing is generous, that is two sizes less than my Magnum's! I have a wide foot so i highly recommend this boot to those people. Straight away as soon as i slipped my foot in the comfort was unbelievable. Nice and light. I highly recommend them, time will tell how they wear.