If you're considering a new company car then it's most likely that you're looking at models with diesel engines.
That's entirely understandable. Diesel engines, with respect to CO2 emissions, tend to be quite clean and they're typically economical.
For a company car driver both of those are important aspects. Lower emissions means less costly monthly company car tax bills, while good economy means less money spent on fuel.
Nevertheless, modern technology means that petrol engines are closing the gap with regards to emissions and fuel consumption.
The facelifted Ford Fiesta is a case in point. Beside a range of cosmetic and kit updates, it's now available with Ford's three-cylinder 1.0-litre EcoBoost petrol engine.
It's a great little engine but just because it's small doesn't mean it compromises on performance.
We tested a version which outputs 123bhp and up to 200Nm of pulling power, granting the Fiesta satisfying performance and a 0-62mph time of 9.4 seconds.
More remarkably, the EcoBoost engine is claimed to average 65.7mpg while its emissions are rated at just 99g/km of CO2. That places the Fiesta in the 10% Benefit-in-Kind tax band.
That's good news for company car drivers. As a result, and with a P11d value of £16,990 for a well-specified Titanium X model, those in the 20% tax band will pay only £28 a month for the Fiesta.
The equivalent 1.6-litre diesel Titanium X model is marginally more expensive, with a P11d value of £17,490, but it emits 99g/km of CO2 too.
Being a diesel, however, it attracts a 3% company car tax surcharge. That's because diesel engines generally emit other harmful gases and particulates.
Consequently, with its higher Benefit-in-Kind charge of 13%, the diesel version of the Fiesta costs £38 a month for 20% tax payers. That's considerably more than the petrol alternative.
Going for the EcoBoost Fiesta instead of the diesel one also brings around other benefits. The petrol engine's quieter, smoother, more engaging and more powerful.
It's not all bad news for the diesel though. Its claimed average economy is a substantially higher 78.5mpg, so with a 40.5-litre fuel tank it can potentially cover almost 700 miles between refills if you manage the manufacturer's claimed economy.
The petrol Fiesta, despite its slightly larger 42-litre tank, can only cover around 600 miles between refills.
Of course claimed average economy and real-world economy can be two very different figures and if you're doing lots of miles then the diesel is probably the more sensible choice.
You'll have to do your sums carefully though, in order to ensure that picking the diesel will save you money compared to the EcoBoost petrol option. By no means should you default to the diesel option without at least considering the EcoBoost version first.
Many will find the EcoBoost Fiesta more enjoyable and relaxing to drive as well, which can make a vast difference when it comes to actually living with a car.
It can even be worth paying a premium for, particularly if you spend lots of time in your company car.
The updated Ford Fiesta goes on sale in December 2012. It will be available in both three- and five-door specification, with a range of trim levels and equipment options.
A variety of engine options will be offered, including conventional petrol units, while automatic gearboxes will be available on some models.
To read the full Parkers Ford Fiesta review click here.
Also consider:
The new Clio is fun to drive and better built than previous models. An efficient 1.5-litre diesel makes it a good option for company car drivers.
If you want a car with a premium badge then you could consider the A1. It's stylish, refined and available with a range of options.
Drivers who want an engaging car could opt for the Swift Sport. Benefits include low monthly company car tax costs and a modicum of practicality.