I had an F10 LCI 520d M Sport from new for 3 years, and I think with a good spec the F10 is a hard car to beat even by new car standards. I was looking at them again and ended up deciding to go for an F01 7 Series instead, and I'm glad I did, it's a fantastic car both to look at and travel around in, and they are great value too for what you're getting.
So, I recently picked up this 2014 F01 LCI 730d M Sport, Black Sapphire, Ivory leather, Anthracite Wood, Soft Close Doors and a few other things, from BMW AUC, 40k miles, 1 owner, perfect history, largely looks brand new. For a big car, in Sport mode (which actually makes a difference on these) it drives brilliantly for the size, the engine has more than enough power and on a steady run it'll get over 50mpg.
As Fox has previously mentioned, the one sticking point is the warranty price, but I'll worry about that in 12 months.