Dunlop Purofort are the only ones I'll buy. My last pair were four years old, worn every day, and are still ok apart from the grip being a bit worn out. Never had cold feet in them. They have several different types to suit all situations. I'd never go for any without steel toecaps if you have livestock. My current ones were about 60 quid and I expect to get a good few years out of them so much cheaper than several pairs of cheapo wellies and with warm feet as a bonus.