Keep the family in it

Britain's love affair with "lifestyle" off-roaders, most of which crunch nothing more demanding than manicured gravel, seems to have peaked. After a decade of dramatic boom (sales rose from under 13,000 in 1986 to over 80,000 last year) 4WD registrations have levelled off. By the end of the year, they may even be in decline.

Not so MPVS. Multi-purpose vehicles - boring vans with windows to cynics, revolutionary family holdalls to the converted - are gnawing into the market across a broad front. Just over 7,000 were registered in Britain five years ago when the pioneering Renault Espace led the field. The forecast this year is for nearer 30,000, with the lion's share going to the excellent Ford Galaxy and its VW Sharan and Seat Alhambra clones. By the turn of the century, it's estimated that 600,000 MPVs a year will have been sold in Europe.

Traditional estate cars have not been the invading MPVs' only victims. Off-roaders - perhaps better described as all-purpose all-roaders - are among their conquests, too. And why not? Size for size, these two specialised breeds have much in common.

The 4x4 Nissan Terrano (the Ford Maverik's twin) and the Citroen Synergie (made alongside the joint-venture Fiat Ulysse and Peugeot 806) may be from different market sectors but they're competitive on price, power and seven-seater accommodation. While the big, butch, all-drive Terrano can clearly out-scramble the front-drive Synergie, it is on suburban tarmac that the two usually compete.

Although similar in size, the Synergie, unencumbered by the weight of a 10-speed, 4x4 transmission system, is considerably lighter - to the benefit of performance and, more significantly, economy. It's also easier to drive, not least because the gearlever, which protrudes from a classy dash, feels less agricultural than the Nissan's. Much as I like the effortless mid-range punch of the torquey Terrano's civilised 2.7 litre turbo-diesel, the 2.0-litre petrol engine of the test Citroen is smoother, quieter and niftier through the gears. Parity in performance (but not in economy) is achieved only when the Terrano's thirsty 2.4-litre petrol engine is pitched against the Citroen's frugal 1.9 turbo-diesel.

Driven with restraint, the Terrano behaves with reasonable decorum. Pushed beyond its natural ambling gait, though, it feels cumbersome. Steering is sluggish and vague, cornering grip modest. Like most off-roaders, the Terrano lacks the stance, agility and tenacity of a low-slung saloon. It's the price you pay for massive boulder-straddling ground clearance and fairly crude suspension designed more for acute articulation than ride comfort. Even on decent roads, the Nissan bobs and jerks harshly, albeit without kettledrum thumping from the big (and very expensive) tyres. The cabin is well isolated from road noise by a separate rugged chassis.

From the driver's seat, the Citroen Synergie looks, feels and behaves much more like a normal saloon. Although the roofline is high the centre of gravity is quite low. Whereas the Terrano perches on the road, as if on stilts, the Synergie, riding on smaller wheels and more sophisticated car-like suspension, squats on it. Handling and cornering benefit from this, though the ride is disappointingly agitated.

You sit a couple of inches taller in the Terrano, all the better for sightseeing and hazard spotting. However, the versatile Synergie has the more imposing cabin and dash. Its individual seats - rows two and three served by easy-sliding doors - can be juggled around or discarded altogether. In the Terrano, only the uncomfortable rear bench can be removed. With all the seats in place, luggage space is pretty meagre in both cars.

If you really need mud-plugging, bank-climbing, stream-fording, precipice- defying transport, the Terrano's your car. Recent major improvements have elevated this rather gawky-looking vehicle from wimp to warrior, built like a tank and well endowed (the turbo-diesel is all muscle). As a road- going people carrier for the urban jungle, though, it is over-specified and under-achieving. The Synergie - a good MPV but not the best - makes a better job of transporting seven adults (if not their luggage) speedily, economically and comfortably.

Citroen Synergie: Price: pounds 16,200 to pounds 23,090 according to specification. Engine: 1.9-litre, 92bhp turbo-diesel or 2.0-litre 123bhp petrol. Transmission: five-speed manual gearbox, front-wheel drive. Performance: top speed 99mph; 0-60mph in 13.9 seconds, 31.7mpg urban cycle (diesel); 110mph, 0-60mph in 12.1 seconds, 23.9mpg urban cycle (petrol)

Nissan Terrano: Price: pounds 16,600 to pounds 23,100 according to specification. Engine: 2.7-litre, 125bhp turbo-diesel or 2.4-litre, 118bhp petrol. Transmission: five-speed manual gearbox, part-time four-wheel drive with selectable low-ratio, auto-locking front hubs. Performance: top speed 96mph, 0-60mph in 16.2 seconds, 22.6mpg urban cycle (diesel); 99mph, 0-60mph in 14.3 seconds, 17.9mpg urban cycle (petrol).