Should one get excited when a serious person, though also something of an academic outsider, claims to have solved several of the biggest open problems in physics? Marcus du Sautoy thinks so, and he has seen the details. Ed Frenkel takes it seriously, though in a more let's-wait-and-see way. The best I can say from my utterly non-expert perspective is that it sounds as though it is interesting work even if it turns out not to be the long-sought theory of everything, but that at the moment one's level of excitement should be similar to what one gets when reading of a new development in cancer research that might greatly improve treatment one day. Most of those stories you read once and then never hear of again, but presumably some of them actually do lead to improvements. Importantly, one shouldn't be excited until a lot of physicists have looked at the work sceptically and had a chance to say, "Yes, but if that theory were correct, then how would you explain X, Y and Z, which appear to contradict it?"
A final thing that goes without saying: the fact that this is written about in the Guardian is not a reason to get excited.