When Renault introduced its 1.5-litre dCi turbo diesel engine to the last-generation Clio it immediately became one of the most easily recommendable power units in the range, and that remains the case now. Although the new Clio is larger than the model it replaces, the dCi copes exceptionally well with the extra bulk, giving performance that is more impressive in real life than the plain figures suggest, while also returning fuel economy above 60mpg on most trips.Added to that, the Clio's noise suppression could almost make you believe that the dCi isn't a diesel at all. For such a relatively small car, the Clio is impressively quiet considering what's under the bonnet.I'm not quite so sure about the changes that have been made to the rest of the car. There's more room than there used to be - in particular, rear passengers used to be very cramped in the Clio, and they are better served now, though it's still a little tight back there for tall adults. And for the driver there's something just not exactly right about the seating position.Looking at the steering wheel, I don't find that it's unduly tilted forwards at the top, but it feels that way when you're using it; the instruments definitely do have a slightly awkward forward tilt to them, so perhaps I'm just suffering from an optical illusion. Either way, the effect is that the Clio is a little less driver-friendly than some of its rivals.I was assured quite vehemently, on a long cross-country run, that it doesn't represent the apex of passenger-friendliness either. There's no particular need for a car like this to handle in a sporty manner, though I quite like the fact that the Clio does just that. The flipside is a firm ride from a chassis which reacts almost angrily to bumps, as if it's punishing them for daring to disturb the journey.The least appealing feature of the car is one increasingly shared by small three-door vehicles. In their efforts to make the rear look sexy, the designers have fashioned side windows which taper towards the back, and while I can imagine Renault people congratulating each other on the visual effect I also wish someone would have taken the trouble to climb aboard and establish whether they could see out.If they had, they would surely have been appalled, and demanded a rethink. The Clio's rear visibility is absolutely terrible. It would be quite possible for a child to walk straight into the path of the car as you were reversing into a parking space, and for you to know nothing of it until you heard the anguished cries of an appalled parent. If manufacturers don't start doing something about this soon, legislators may have to do it for them.At the other end of the car, Renault has made a significant contribution to road safety which we certainly will be seeing from its rivals in the near future (it applies, for example, to the Peugeot 207, which at the time of writing has been made available to the media only as a static display). Some cars these days have headlights which swivel according to turns of the steering wheel; the Clio, on the other hand, has fixed headlights plus supplementary lights to each side which illuminate the area diagonally in front of each corner as they are required.Other road users seem to find this a bit of a mystery, and I hope I didn't dazzle anyone. From the inside, it's a superb system, with a definite advantage over swivelling lights - since the normal beam isn't affected, you don't have to wait for the lights to react to the steering being straightened after the corner.This set-up and the dCi engine are the two reasons I was sorry to see the Clio leave. The disappointment at the fact that the new car isn't leagues ahead of the old one, along with the disdain for how badly the rear visibility have been compromised, are the two reasons I didn't mind not being able to keep it for longer.