BMX X5.
I may be a bit biased as I own one. Awesome car will never go back to another car.
Pros:
- Easy on the eye
- Powerful, it is bit blokey though, but everyone looks good in BMW
- Very nice interiors, and have sensor for everything, will let you know which break pad is more worn out than the other, Tyre pressure loss, rain sensor screens, individual air con option for driver passenger etc.
- If you are petrol head like me you'll love it, I have Diesel one XD30 twin turbo which in theory shouldn't be as fast as petrol ones, but no one has ever beaten me when accelerating at traffic lights
- Colour especially Black one, even after 6 years when I wash it looks brand new
- BMW service, they'll treat you like a king, once you come in, butler will offer you a glass of water, make you a coffee of your choice. Also, they always fill in your tank no matter how low when you drop in for a service
- Customisation, you can have pretty much anything as long it is legal, TV in the back, a different mirror, extra wood on dash board, you name it and you can have it.
- Fuel economy is pretty good, X5 has 85 litres tank, you'll get pretty close to 700 ks in normal conditions, and more than 800 ks on freeway.
Cons:
- Cost, especially if you want M series one, even the basic one (not M series) here in Australia will cost you more than 100 grand, and M series ones here in Australia start at 150 grand plus. But hey, you don't buy BMW for logic. That said, I suppose cars are cheaper in UK as compared to Australia
- Particle Filter Issue for Diesel ones XD30, XD35 and E70 models, especially from 2008-2013 if you are buying second hand. Google it you'll plenty of info on this one. I did not have this issue with mine (2010 model) but I did get particle filter sign but luckily it was a sensor issue
- X1 and X3 in my opinion does not have same driving experience as X5, they just want to make a car for every spend class but its not the same as X5. I suggest go for a test drive before making a decision, those are almost half the price of X5.
- Service will cost you an arm & leg if you go to BMW, especially labour cost, BMW is called Break My Wallet for a reason. You can mitigate that by finding a good BMW mechanic, however, if you take extended warranty, then you don't have a choice, you had to go BMW
Don't know much about Mercedes but SL/CLK/SLK are very easy on the eye, however, their SUVs are not very aesthetically pleasing.
Audi, just one comment, they are not there yet, stay away from Q5, heard very bad things about it, and somehow very easy to steal. Most stolen car in Melbourne.
Hope it helps you in making a decision.