It’s no secret that British car buyers treasure premium badges. Brands with upmarket images have done enormously well here in recent years, feeding off our tendency to value their higher build quality and more generous equipment – not to mention the status they bestow upon their owners.

Nowhere has this been more the case than in the executive car market, where mainstream manufacturers like Ford and Vauxhall once dominated with large five-door hatchbacks. Yet today, they’ve been usurped by their upmarket rivals, with BMW and Audi even going as far as to introduce similar models in recent years – albeit with a spot of marketing gloss that’s reinvented them as four-door coupés.

So is it still worth buying one of those mainstream executives brand new any more? Or, for the same budget, should you plump for a year-old premium rival instead? Well, that’s what we’re here to find out.

First up, representing the mainstream brands, there’s the Vauxhall Insignia Grand Sport. We’ve picked the top-spec Elite Nav version, equipped with the 2.0-litre diesel, to give it a fighting chance against our used premium contender, the BMW 4-Series Gran Coupe. For less than the target price for our brand-new Insignia, you can buy one of these in 420d Sport form, at a year old and with 10,000 miles on the clock. Tempting, no? Time to find out which stacks up as the most sensible buy.

Vauxhall Insignia Grand Sport 2.0 Turbo D Elite Nav List price: £26,525 Target price: £25,767 Official fuel economy: 51.4mpg Emissions: 144g/km CO2 Power: 168bhp 0-62mph: 8.2sec Top speed: 140mph

BMW 420d Sport Gran Coupe Price new: £35,615 Price today: £24,975 Official fuel economy: 62.8mpg Emissions: 119g/km CO2 Power: 187bhp 0-62mph: 7.5sec Top speed: 149mph

Price today is based on a 2017 model with average mileage and a full service history

New Vauxhall Insignia Grand Sport vs used BMW 4 Series Gran Coupe – interior & equipment

It might be a premium contender, but the 4 Series’ dashboard isn’t quite as smart as you might expect it to be. This is an old design of car now, and its slightly cluttered centre console shows its age. Having said that, for the most part the 4 Series is a pleasant place to be, with truly high-quality plastics that feel upmarket and leather seats as standard.

The Insignia gets leather as standard, too, but it doesn’t feel quite as upmarket as the 4 Series’ – and the same can be said for the rest of the interior. Plastics are clearly a grade below, while the buttons and stalks don’t move with the same sort of glossy slickness. And while the centre console is certainly easier to navigate, the flipside is a button-laden steering wheel.

In terms of its infotainment, too, the 4 Series has the edge over the Insignia. The BMW system, operated by a rotary dial, is easier to use on the move, making it less distracting, and its menu system and on-screen graphics make it more intuitive. The Insignia’s set-up is slick and responsive, but its touchscreen interface is just a little more fiddly and its graphics don’t look as smart.

You do at least get everything but the kitchen sink thrown in with the Insignia. Adaptive LED headlights, heated front seats and a Bose stereo are all standard-fit. That said, it’s not as if the 3 Series feels basic; true, you don’t get a few of the Insignia’s extra fripperies, but all the bits of equipment you’d really want – including dual-zone climate control, sat-nav and rear parking sensors – still come as standard.

New Vauxhall Insignia Grand Sport vs used BMW 4 Series Gran Coupe – space & practicality

Let’s start in the boot, where both cars are relatively evenly matched. However, of the two, it’s the Insignia that wins out – its boot is larger whether the rear seats are up or down, and what’s more the boot opening is wider and squarer with a lower lip, and the boot itself is a more useful shape.

In the back seats, again, the Insignia is the most spacious, with more head and leg room on offer. And while the 4 Series offers enough room for two adults to sit in comfort, it does feel a little more cramped.

Thankfully, front-seat passengers won’t have any such issues, as both cars offer a similar amount of room. And while both driving positions offer lots of adjustability, the 4 Series’ is slightly compromised by its offset pedals.

Next: What are they like to drive? >