My old man currently has a 4.4i E53 and he's switching to a 3.0si E70... he had a test car for 24 hours a month ago and I got to drive it.

Now there is an abovious power drop from the 4.4's 315 hp to the new 3.0's 260 hp (not 272 hp in North America), but I honestly didn't feel a huge difference. Yes response and acceleration were slower but I felt it was adequate for the car. Even though I read a few reviews that say otherwise, the E70 to me feels much lighter and more dynamic than the E53. Plus the fuel consumption is much better with the 3.0.

So to sum it up, adequate power, good fuel economy...

Now in terms of power differences, BMW quotes the 260 hp 3.0si version's 0-100 to be 8.3 s, while the 272 hp version does it in 8.1 s. So you gain 0.2 s in acceleration which is not really noticeable.

Now if you're not in a hurry to buy, maybe wait for the 3-litre twin turbo to be introduced, which should shave off probably another slight 0.3 s or so... if performance is very important to you that is (but if it is, I suggest not getting a truck).