I had a brand new F30 320d for a courtesy car the other day.
It wasn't bad at all, it accelerated nicely, it was comfortable, looked ok (from the back and sides - but i guess this is just because it looks almost identical to an LCI E90 from these angles), but looked a bit pap from the front (was an SE).
It did roll quite a bit more than my E92 and the interior most certainly is not better than the E92. It is leagues away from the F10, and very much reminded me of the MK5 Golf interior -well put together, but there were some questionable plastics in places.
The engine. After hearing from all sorts of people that modern diesel engines are so refined these days, i got my chance to see if a 2012, 500 mile diesel engine from one of the best car manufacturers in the world could be classed as "refined". It couldn't.
As someone who isn't used to diesel engines, i was shocked by how rough and rattly it was when it started. This was to the detriment of the Auto Start/Stop feature (which caught me out the first time it happened!) as when i was ready to go, the engine took a fraction of a second longer to roughly rattle into life than a petrol engine would have. The gearstick shook like a terriers tail (Get in! My first Clarksonism!) when the engine was started, it dag dag dag'd like i thought it would and, contrary to what some people say, i was still VERY much aware that it was a diesel, even at 40mph.
Overall, a bit disappointed with the so called "modern diesel refinement". However, what i wasn't disappointing with was the 52mpg i got out of it with no effort whatsoever. The 320d is a perfect car for someone who really doesn't care about cars. It is comfortable, well built, quick enough and handles well. However, for someone who does like cars (like me), a 320d just simply does not cut the mustard. It is boring, bland and the engine not as refined as i thought it would be. Would very much like to try a 6pot diesel though!