To the original point that you seem to disagree with - I think the person making that comparison will agree that the show is built around Guinness in a way the film is not built around Oldman. I don't think that's wrong, and which is "better" must be a point of personal preference. One could not make a show with Alec Guinness any other way, and the result is certainly worthwhile.
It really is a great show and of course I'd encourage anyone to watch both. A person reading your comment might end up being a little disappointed, though. The most eminent name on that list, and the one people outside the UK are likely to recognize, does not even have a speaking part.