I have driven my X3 30D for over two years and 35000km now and I have been very happy with the ownership experience. I bought this model due to the quality, space of the cabin, and value for money considering the features and superb driving traits.
The power and economy of the 6-cylinder, 3.0-litre, 195kW/620Nm diesel is simply outstanding. Imagine sub-6.5 litres per 100 kilometre fuel economy around the city and acceleration of 0-100km/h in under 6 seconds. I usually get 1000km to a full tank. It has tremendously smooth, linear power coupled to the best automatic on the market. There's just a slight clatter off idle that gives away the engine.
Where it really shines is when towing. I frequently tow an almost 2-tonne van and ski boat, which the X3 does with aplomb! There's so much effortless power in reserve for any situation. It even holds top gear going up a hill. Towing the van returns economy around 12L/100km, and pulling the boat gets 8L/100km. My previous Kluger used to drink almost 20 litres!
The ride is definitely firm but liveable. Cabin space is acceptable for a family of four (I use a luggage pod on big trips). The M Sport seats are comfortable, and very adjustable. Also featured is the typical BMW user friendly iDrive. I love the way BMW angles everything toward the driver and has buttons for all the features, as apposed to touchscreens.
Bluetooth connectivity is excellent over multiple phones, featuring audio streaming and apps - it all just works. The Active Cruise Control is just flawless, the parking with all the sensors and cameras is a dream, as are the LED active headlights. Where have they been all these years? It even knows where the roundabouts are and puts the sidelights on to illuminate them.
The main thing I love about this model is that it's not overly big, and on its own in Sport mode it can essentially be a hot hatch - it really does perform! Then when family time comes, it's big enough to tow and carry everything we need for the family with the pod.
For any improvements I can consider, there's not a lot - maybe a softer ride. It has been extremely reliable except for a DPF-related issue, which was fixed with a software update. I have 5 years free servicing and the dealer has been very good.
I am keen on the 30E hybrid when it comes out. I almost think that would be a perfect machine.