The Audi A1 is the baby of the Audi family with its cutesy hatchback styling setting it apart from the larger and more serious-looking Audi A3. It shares similar front styling to its larger brother, giving it a slightly aggressive look from the front, but glance down the side and around the back and things are a little more bubbly and a lot more fun.There are two versions of the A1, the standard 3-door version and the 5-door Sportback, giving you back doors for your passengers' convenience. It's a nice enough looking small car, although the short roof means a rear that slopes off rather less sharply than some. That doesn't impinge on the size of the boot however, with 270-litres of storage, about the same as the VW Polo.\u00a0The design seems to pick a middle ground between traditional hatch and supermini. But it's a design that's attracting plenty of drivers judging by the number of Audi A1s on the road. We also liked the split colour scheme with a silver roof - although that's an option that will cost you \u00a3400 - which gives it a distinctive look, in a similar way to the Citro\u00ebn DS3.\u00a0We suspect that the number of Audi A1s on the road may also be down to the starting price of just over \u00a314k for the 3-door, for which you'll get a 1.2-litre petrol engine with SE trim. The 5-door Sportback starts at \u00a3600 more, with the same engine and trim, but it's the most affordable route to a new Audi and that four-ring badge is certainly en vogue at the moment.The Audi A1 Sportback we got our hands on, pictured here, however, was at the other end of the scale. With a 2.0-litre TDI diesel engine and S line trim, this model starts at just over \u00a320k, before you start piling in some of the options, bring the final on the road price for what you have here up to \u00a325,940.\u00a0It's worth keeping an eye on those prices and options, because by the time you get up to that level, you could get the same great engine in the excellent A3 Sportback with S line trim.Internally, with the S line trim and Black Sprint cloth and leather finish, it's a nice place to be. The high position of the driver's seat suits the sort of driving that compact hatches often do and that's darting around urban areas. There's plenty of visibility so you can see what's going on around you and the compact nature of the A1 means it's easy to get in and out of those tight parking spaces and so on.The comfortable seats provide plenty of support lending to the sporty feel that Audi wants the A1 to impart, but the interior design is distinctly Audi, reflecting many of the features you'll find in the other cars across the Audi family. Things are sensibly laid out once you're in the driver's seat with the convenient controls on the steering wheel. The Audi A1 makes some compromises in sitting at the entry-level, with a slight drop in the interior quality from bigger models. The dials of the climate control and the driver's digital display don't give quite the same impression as they do elsewhere in the range, even if they compare favourably with rivals.The steering wheel, however, in the S line trim, does feel lovely with its leather finish and it's these touch points - steering wheel and seats - which we think are the most important. No complaints in that department, then.Equipped with the 2.0-litre 6-speed manual, our test Audi A1 was fitted with an engine you'll find widely across the VW-Audi group. With 143PS at your disposal, it's quite a lot of power for a small car. If it's speed you're after, there's the option for a 185PS 1.4-litre TFSI petrol which will make it a little more racey on the roads, but we suspect some will save their cash and opt for something slightly smaller.But with a big diesel under the bonnet, the Audi A1 Sportback will happily speed you about the place without having to worry about losing power when you hit the first hill, or when you decide to use those back seats to port your children around.However, the first thing we noticed about the TDI was the noise level, which is pretty noticeable within the cabin. It's not the sort of symposer-enhanced sports car noise you'll get in a Ford Fiesta ST, as you're listening to a big 2.0-litre diesel. But there are a number of great engine options, so it's well worth a test drive to see what fits your requirements in the real world.We turned the excellent Bose sound system (a \u00a3690 upgrade) up a few notches, tuned in the radio and set off down the roads of Warwickshire to enjoy the power as well as the economy, with Audi saying you'll get close to 69mpg on a combined cycle from this engine. That should put a smile on your face, even if the slightly harsh S line suspension could be a little firm for some.A great little fun car to drive, it's obvious why we've seen a growing number of Audi A1's on the road. We're not totally convinced that the 2.0-litre diesel will be the best option for all, but there's no shortages of options on this baby Audi.