At one time they had every base covered between them: Saab was the wacky one that sold idiosyncratic, turbocharged executive hatchbacks, steeped in aeronautical history, while Volvo was the sensible one, knocking out perfectly square estates for perfect squares.
Saab's head was in the clouds, and Volvo thought inside the box. They complemented each other. But then General Motors came along to take Saab, and promptly misplaced its mojo; Saab went sensible too, but it couldn't do it as well as its neighbour.
Cut to the present and Saab is in absolutely dire straights, while Volvo is fitter than ever. And what's more, almost every Volvo these days is rakish, swoopy-sporty, even.
That's almost every one. There's still the S80. It might have seemed hip and thrusting back when the first one was launched in 1998, but this second one - launched in 2006 - looks very similar in 2011. Today, it's languishing near the bottom of the corporate ladder.
Above it, of course, are the BMW 5 Series, Mercedes E-Class and Audi A6; each extremely good executive saloons, but in slightly different ways - you pay your money, you take your choice.
But if you want to pay less money, the S80 really does have something to offer - and it's not just being cheaper than the Germans.
For a start, it's inconspicuous. That might be a negative for you, but when there are so many of the aforementioned German executive cars on the road, the Volvo is understated. It's attractive in a non-flashy sort of way.
The best thing about the S80, though - and the thing you'll notice within a mile of first driving it - is its refinement. The Swede's ride quality is exemplary, limo-like in its ability to iron out the road.
That's aided by one of the best driver seats in the business. It lacks the side support of some rivals' chairs, which can sometimes feel like they're squeezing their occupants for information, but it's soft and contoured perfectly. It's set slightly too high, but some armchairs are less comfy.
To Volvo's credit, the company hasn't tried too hard to make the S80 a sports saloon, even though there's a sport chassis option, so while that means it doesn't provide anywhere like the driver enjoyment that a BMW 5 Series can, it is a very stress-free ride to pilot.
For example, the steering is feather light and very direct, so it takes very little effort to get the car turning. Parking and low-speed manoeuvres take minimal effort, but try and drive with any sort of enthusiasm and the S80 leaves a lot to be desired.
Part of its dynamic shortcomings are down to its front-wheel drive layout, which gives rear passengers a bit of extra leg space, but makes it unique in the executive segment: all its rivals are rear-wheel drive, and it has nothing like their sense of handling balance.
However, the engine of the car we tested is a real highlight - so it's a shame it won't be sold here in the UAE. It's actually one of only a few things that have been tweaked in the S80 for the 2012 model year; the S80 had its major midlife facelift last year and these minimal changes seem to have been made largely to keep the car on the collective executive radar.
It's stuff like moving the indicators into the door mirrors, adding a couple of new wheel designs, changing the steering wheel design and the instrument panel slightly and fitting a couple of extra safety features as standard. It's the equivalent of turning up to work one day with the same old shirt and tie you always wear, but with a new pair of cufflinks.
Anyway, back to the engine. The D5 diesel is changed in a Eurocentric sort of way, with more power but significantly better fuel economy and emissions, meaning lower tax. In fact, the 212hp unit is, on paper, more impressive than anything the Germans are doing in terms of power-economy ratio. With 4.9L/100km combined, it's a fat cat running on skimmed milk.
It's quick, too, and because it has five cylinders it sounds more raucous than an average diesel. Enough of that though - the petrols are the important engines in the UAE, and they stay the same, with the punchy 304hp T6 spearheading the range.
But, again, speed is not what this car does best - comfort is, by a long way. In fact, the S80 is so comfortable and its cabin so simple and intuitive that it's difficult to muster up any sort of enthusiasm for it; people get excited about speed and loudness, not sober functionality. Who ever shouted on about their awesome new shelving unit?
Yes, the S80 still has the trademark "floating" centre console that seemed sensational in 2004, but today it has lost its novelty value. The buttons are big and easy to decipher and it all seems very high quality, but it's so straight-laced that it makes the Audi A6's cabin seem like a party of postmodern design.
But that's the point - it's easy to use, no nonsense. The S80 is arguably the last bastion of old school, conservative Volvo, especially now that the S60 has gone all sporty looking.
It's exactly the sort of safe, unassuming and high-value car that Volvo used to be famous for. It's quiet and soothing. You can sit in it for hours then get out feeling like you've had a massage.
Let's hope Volvo sticks with what it's good at when the next one comes along because it doesn't want to go down the same road as Saab.