For me they aren't as good, for the simple reason that there's now not enough difference between the two people. By having two people who are similar age, similar physical appearance and who are known as a double act it destroys the illusion that they are two radically different sorts of computers.
Despite being a Mac enthusiast and knowing exactly what the ads were about I find myself asking "well what is this advertising". Which I think is a flaw of the original adverts magnified by the new British versions... namely that the ads are all about PCs without really saying anything about Macs. At best you come to realise that whatever they are talking about as being a negative for PCs is something that Macs don't have. To put it into perspective I think the most effective US adverts are the ones where the Mac is the focus. The more the Mac guy talks the better of an advert it is, simply because its getting more of the Mac message across. When its all PC, PC, PC except for a line or two about "oh that's interesting" I don't see what message the average consumer is actually going to pick up.