The Kia Optima had been refuelled immediately before I sat in it for the first time, and its range predictor told me that I could expect to enjoy well over seven hundred miles' worth of motoring before I needed to trouble its filler cap.I chuckled immoderately at this. Thighs may even have been slapped. Surely the Optima's predictive electronics were having me on, and would tell a much darker story as I began to use up the second half of my diesel allowance? Well, no. The fuel warning light didn't flash on until 723 miles of predominantly motorway driving, and as I refilled at 750 the computer seemed to be suggesting that I wasn't being very sporting about this and could have gone quite a bit further if I'd tried.This startling range bespeaks resounding fuel economy, or a large tank, or a combination of the two. The Optima's tank is class-averagely big: it holds just over 15 gallons, the same as those in the Ford Mondeo and Vauxhall Insignia which, if you are in the market for a D-segment family car, are what you will probably buy instead of this one.As for the economy, during this test I averaged a little over 53mpg, which isn't so far away from the EU combined figure of 57.6mpg. It's also about what you'd expect, these days, from a diesel saloon of this size, perhaps a little better, and it's helped by the fact that the only engine you can have in a UK-sold Optima is a relatively small 134bhp 1.7-litre diesel.The straightline performance it provides might be described as "adequate". If you like charging around the place you'll regret that Kia doesn't offer a more powerful alternative, but for relaxed everyday motoring it's fine. And there isn't much about the Optima that would make you want to drive it in a sporty manner.It doesn't handle especially well, being easily confused even by quite small bumps, such as are to be found throughout this country's motorway network. The fact that the test car, being in 2 Tech spec rather than the identically-priced 2 Luxe alternative (more details on that shortly), had 17" wheels and not 18s means that its steering isn't as sharp; it should also make the ride quality better, but having driven one of each car on the same day - see launch review - I can tell you that there isn't actually all that much difference.In the Optima range, the 3 is the best-equipped model, while the 1 is unique in costing less than £20,000. The most popular choice in the UK is expected to be the 2, which as previously mentioned is split into Tech and Luxe. Apart from the smaller wheels, the Tech tested here has black cloth/leather upholstery, a 12-speaker Infinity audio system and satellite navigation with a 7" touchscreen. The Luxe is more style-led and has a more basic audio and no satnav.Of the two, I'd go for the Tech largely because of the satnav, which is clear and has, if not industry-leading graphics, certainly perfectly good ones. Graphics in fact seem to be becoming a Kia speciality; in the range indicator part of the dashboard display, as well as in several others, Kia has not simply used a generic 2D representation of some kind of generic bubble car, as most manufacturers would, but has taken the trouble to create a rear three-quarter view of what is quite definitely an Optima.This is just part of an attention to styling detail that has made the Optima one of the most attractive cars in its class both inside and out, perhaps rivalled only by its stablemate, the Hyundai i40. In each case, good looks hide the fact that these are not especially high-quality cars, at least not when compared with the aforementioned Mondeo and Insignia.Of course, they're priced accordingly, and to use a well-worn phrase it would be reasonable to describe the Optima as a Mondeo-sized car for Focus money (insert "Insignia" and "Astra" where appropriate if you prefer). That's quite appealing. In fact, when you add that factor to the looks, the economy and the usual Kia seven-year/100,000-mile warranty, you end up with a compelling set of reasons to buy an Optima. Engine 1685cc, 4 cylinders Power 134bhp Transmission 6-speed manual Fuel/CO2 57.6mpg / 128g/km Acceleration 0-62mph: 10.2 seconds Top speed 125mph Price £21,695 Details correct at publication date