Jaguar versus Aston Martin is a bit like Senna vs Prost or Borg vs McEnroe in that, as an enthusiast, you tend to be a fan of one or the other, but not both. There are Jag people and there are Aston people, in other words, and while the products themselves often share an uncanny resemblance to one another, the brands from which they emanate are subtly different.

Aston Martin has a tangibly suave allure about it, a shaken but not stirred cool that distinguishes it as being something that’s almost priceless. A Jaguar, on the other hand, is more the people’s luxury car – a friendlier, more attainable, but still resolutely British icon that’s usually cheaper and less rare than its equivalent Aston.

Except nowadays, of course, Jaguars are becoming increasingly expensive, and although Astons aren’t exactly dropping in value by proportion, the gap between the two has shrunk to the point of almost total non-existence. Which is why it was interesting to compare our long-term XKR-S convertible (£105k with options) with our V8 Vantage (£102k with options) for a video we shot just last week.

The Aston is a lovely car for all sorts of reasons, not least of which is the way it looks. It has something about it outwardly that makes you smile. It is beautiful from pretty much every angle, and although it appears quite small – dainty, even – beside the bigger and brawnier XKR-S, it is unquestionably the more elegant of the two. Not just outside but inside its hand-crafted cabin, too.

And yet… There’s something about the Vantage that seems curiously unsatisfying alongside the XKR-S. In simple terms, it’s fairly obvious that it can’t deal with the Jaguar dynamically and it’s nowhere near as powerful (420bhp vs 542bhp), so isn’t anything like as quick. It also has a far less soothing ride and generates a lot more road noise at anything above 2mph.

But even if you ignore the headline stuff and focus on the details, the only aspects that distinguish the Aston are its looks, cabin quality and badge. Just about everything else – engine, performance, gearbox, ride, steering, even the exhaust note – is better in the Jaguar. In most cases, much better.

Which means what, exactly? Are Aston Martins now redundant because Jaguars have become so good? Not at all. But the writing is on the wall for Aston, and the news is this: the products simply must deliver more in future to remain competitive within their price ranges. Otherwise one day the customer will simply walk the other way, given that there’s so much excellence on offer elsewhere. And if that happens, not even James Bond will come to the rescue.