I've been driving my 280 for 4 months, 5K miles. It's a pretty good car but the overall perceived quality is lower than I expect on a Mercedes. I had a couple of rattles, in fact I still do, but the dealer has been patient enough to check it. Still not up to what I'd expect, especially as a prior BMW owner. The drive is fun and the 3.0 engine is more than enough. I do find that it takes a little time to respond to a "full gas". The trunk is deceivingly spacious, enough for a couple of beach chairs, umbrellas an a picnic bag. But it lacks some in cabin storage, especially if you opted for the 5-disc changer that takes up your glove compartment's miniscule space.
Of course the hard top; that's what steered me away from the Z-4. The interior/exterior design in general is great. The 7-speed transmission is great too.
Improve the location of the cup- holders, add a garage door opener, and compass standard. But for God's sake add a decent base sound system with in-dash changer, and bluetooth phone instead of the $1500 phone option that only takes 2 phones that Moto doesn't make anymore.