I never drove the 535d. But I did own a mapped 335d before getting my F11 530d.
Do I miss the extra power I had in my 335d? Occasionally yes. But I am happy with my choice. As Fox said, it is an astounding package. So yes, I am very happy with my choice.
The engine, coupled with the gearbox consistently surprise me just how good the combination is. My 335d didn't have that box, and it is a revelation. The 530d almost feels as fast as my 335d did when standard. And that has to be down to the gearbox.
The 30d engine is obviously a compromise option. But it is a worthwhile compromise. It will cost a little less, and will be a little slower, true. But, day to day driving, it will hardly be noticeable. But day to day driving, you will get better fuel economy. Albeit marginally. But that is, presumably, one of the reasons your looking at a diesel instead of an M.
My 530d has just turned 10k, and is settling down to over 40 mpg tank averages. For a car as big and quick as this, that really is astounding. My 335d was only a couple mpg worse mind you, but the 5 is a bigger, heavier car.
Of course, if you are really wanting the power, then go for the Alpina. A 350 BHP 535d. Although admittedly, I am not really a fan of Alpina styling. I would love an Alpina tune on my car.