I snapped one of their 1/2" breaker bars standing on the end of it trying to undo the truck wheelnuts; when I took it back the bloke looked at it and asked what I'd been trying to undo with it. When I said "wheelnuts" he just smiled and got me a new one!
Friend of mine did the same thing undoing a hub nut - and had the same experience in Halfords.. (I know a weak point with the breaker bars is that the threaded 'pivot' on the end unthreads itself over time - if you don't tighten it up you put all the torque on 2/3rds of the joint and it eventually gives up)
But ditto on everything really - the Halfords Pro (Advanced, now) stuff I have is every bit as good as the odd bit of SnapOn or Britool I've got, and it has a lifetime warranty just like SnapOn.
(And you're right, it's the black 'industrial' toolchests that are the good ones - I picked up the two for £350 earlier this year. Just about put my back out getting them out of the Omega, mind!)