There is an old saying in acting, 'If it looks like you are working, you are not working hard enough.' The same could be applied to much of the Ford Focus - you don't notice many of the features because the designers worked so hard to make them unobtrusive. When you come back to the Focus after driving a different car, you realise how easy it is to live with. For example, its Bluetooth phone connection never fails.

That may sound simple, but we are continually amazed by Bluetooth systems in other cars that have the attention span of a fruit fly. A recent £50K Discovery HSE test car would never hold the connection for more than an hour before deciding the phone was an audio device, rather than, you know, a phone.

Similarly, after you have got used to the Focus's DAB radio switching off when the driver's door opens, not when the engine is cut, you wonder why every car cannot do that. Or the handle on the inside of the boot to close it, which is an actual handle, not just an awkward cut-out in the plastic liner of the bootlid. Finally, the Focus Ecoboost has the smoothest stop-start system we have yet encountered - there really is no reason ever to switch it off.

Anyway, enough of the convenience features - what of the driving experience? One of our trips was to drive the new BMW 116d in the Sussex lanes around Goodwood. Despite the rear-drive configuration and the BMW badge, the Focus was actually more fun to hustle along winding roads.

We thought the BMW had nicer steering, and no doubt, the more sporting set up of the larger 1 Series cars would have turned the tables, but we were nevertheless surprised that the super-refined Focus could out-handle the base 1 Series.

Of course, the key feature of our particular Focus is the Ecoboost engine. The idea is the 150 bhp turbocharged engine, with its advanced double variable valve timing, makes petrol engines competitive once again against diesels. Now, we are not usually short of opinions about cars in this office, but this question of Ecoboost v. Diesel is not an easy one to settle.

On the plus side, the Ecoboost really is a step forward for petrol engines. It is very smooth, sounds mildly sporty at high revs and gives no hint of its turbocharging - the power delivery is very strong at low revs and is linear all the way through the rev range. The downside is that, while more economical than any previous 150 bhp petrol engine, it is still not up to diesel standards. Living in central London, but mostly using it for fairly long trips, we are getting 38 mpg overall.

A similarly priced 1.6 TDCI would be getting over 50 mpg in similar use, but would only offer 115 bhp. A similarly powerful 2.0 TDCI would cost around £1000 more and achieve 43 - 44 mpg. It is clear that Ford has priced the Ecoboost very carefully: over three years, the extra cost of the fuel for the petrol engine pretty well matches the extra initial cost of the 2.0 diesel. Thus it comes down to personal preference. The Ecoboost gives a sportier drive, but will probably cost a little more in the long run, as a used diesel is likely to be worth more on the used car market than a petrol engine.

It is easy to see why Lower Medium hatchbacks have become the default choice for so many families - big enough to fit everyone in, while being easy to drive and relatively affordable. It is also easy to see why the Focus has long been the default choice within the segment.

The latest model is more sophisticated and more polished than its predecessor, although its steering is less sharp than it used to be. For most people, most of the time, that is a trade-off that makes sense. Unfortunately, most of us spend most of our driving time either in town, where the Focus's silky drivetrain makes it very easy to drive (anyone who can't drive this car smoothly can't drive), or on the motorway, where the Focus is an exceptionally refined cruiser. As car enthusiasts, we have to admit that losing a little sharpness on twisty country roads is something you only notice 5% of the time, whereas the benefits are obvious 95% of the time.