Going by the numbers alone, the sleek Z4 performs very well, accelerating faster than such natural competitors as the Mercedes-Benz SLK250 and Audi TT and garnering better fuel economy -- an impressive 28 mpg overall. Another big draw is the retractable hardtop, designed such that with the top down there's little wind buffeting to threaten your hat or hairdo. However, this BMW falls short on the fun-to-drive leader board. Handling is capable and secure but lacks the tactile feedback and thrill potential that a driving enthusiast craves. Besides, the bowstring-taut ride is almost jarring at times and the cabin, though well finished, is a snug fit for folks of even average girth.