I have 10,000 miles on my 3.0si E70. The only issues I've had were a faulty back up camera (fixed) and sticky door
handles. (fixed). I have had a 3.0i E53 in the past, and although I've said this before, I'll say it again for you Barry.
The E53 was raw. That was both good and bad. It was raw in a good way because of the engine, which I loved. I liked the raw power and thrust, and the feeling of acceleration I got in the E53. But, it had a bouncy ride (non-sport), was not so quiet, and just overall less refined. But that's both good and bad. Everything in the E53 was "thin", but very sturdy and tough. It drove well, but lacked that luxury element. Now that I think about it, I have a good appreciation for the E53. I wish I could drive it one last time.
But now for the E70:
The E70 is refined.
It is modern, quiet, muscular, and luxurious. While BMW says it accelerates faster than the 3.0i, you won't know because the engine is quieter and more refined. (both good and bad). I can easily get the engine back into "raw" mode by cracking a window and moving it into "sport" mode. (on the shifter). The ride is
vastly better. While still firm and sporty, it does not bounce and it is well controlled. The interior is also better, an exit from hard sharp edges to edges and curves with a design flair. Quality is better. Doors no longer sound like a tank (
) but close quietly and rattle free. I like the exterior design better, especially the hood. Feels nimble driving @ speeds higher than town/city driving, but steering does get heavy at low speeds and can be annoying navigating the city. But very good feel and precise. Feels much more secure in bad weather, great lights, great xDrive, and overall more sure footed. While the extra size was a concern of mine, it wasn't as bad as I thought. Feels about the same size while driving (bit wider, though) and parking is easy with sensors and camera. Visibility is ok, I think that the A and D pillars should be narrower, but it looks nice so its ok. Don't get me going on iDrive, though. I don't mind the system at all (but could give you a huge list of things I hate, and things I love). I like the radio on it better than the normal radio, but it is hard to mess with the climate control. Navi is good, but takes a while to program, becomes faster with practice. Bluetooth is nice, and voice commands are great. Control stalks (signals, wipers, etc) are much better. Cruise control is easy. Rear seat comfort is much better, and cargo area is much larger. I really like my run flat tires, btw. Overall, much more modern vehicle. You can definitely see the difference between the E53/E46/E39 and E70/E90/E60 generations. PM me if you have any other questions Barry. I know you would be looking for 4.8i, so sorry I can't help there.