Right, I'll admit to having bought one of those "oil drum" ones from Argos that the OP has linked to at the top of the thread.
Actually it was a few years ago and the BBQ was silver in colour, not black, but otherwise looked identical.
It was a faff to put together. The instructions were rudimentary and a fair few "adjustments" were required to get all the parts to fit together, but once it was assembled it was solid enough.
It swallowed charcoal for fun - look at the size of it. A 7kg bag wouldn't fill it, meaning that it needed a couple of seats of fire to get it started and it took a while to get ready to cook. But once it got hot, by heck did it stay hot! The 'adjustable' charcoal tray seems a good idea, but it wasn't really sensible trying to shift it once the BBQ was lit, so it was a bit trial and error.
You could cook a
lot of food on it at one go. Although this isn't necessarily the advantage you might think (try flipping 20 quarter pound burgers at a time) with the searing heat coming off it.
Did I mention it stayed hot? Hot enough still to cook on 5 or 6 hours after the meal? To the point where the remaining embers were still glowing the next morning? Yes, that hot.
Plus the sheer size of the thing meant it had to stay outside and even with a decent cover we only got two summers out of it.
I'd recommend going for the Weber.