I've owned a number of sports cars including two Miatas and an RX-8. This is my first BMW since my '88 535is and it doesn't disappoint. It's performance is on par with more expensive cars, e.g., Boxster, but it is far less problematic and easier to live with in daily driving. It is comfortable, well-made, has a decent trunk and will run with like cars when asked to do so.
Power top; ergonomics; fit and finish; handling; and gas mileage given its speed capability (which I use a lot)
A few more horses under the hood would resolve all the Porsche comparisons in BMW's favor and put it in box with some much more powerful cars. The M3's 333 hp engine would do nicely.