Only when you take off the road at a moderate pace are you alerted to the fast that power delivery isn't quite as measured and predictable as you might have guessed. Since torque off the line isn't stupendous, you'll find yourself stepping on the gas a little too hard from stoplights or out of corners, only having to back off when the engine really comes alive and the boost arrives. And though you don't hear the engine much from inside the RDX—even on full throttle—crack the window just a bit and it makes all the right sounds on the outside; back off the throttle when you're into boost and you get some nice wastegate music.
The transmission—or rather, the way the transmission coordinates with the engine—was about the only thing that prevented us from feeling that the RDX approaches perfection. Going lightly into the throttle, the transmission felt consistently lumpy on the shift from first to second; accelerating moderately, it smoothed out. Also, we felt an unrefined torque-converter shudder whenever we'd backed off at highway speeds and then reapplied the throttle. From Drive, you can manually select a gear with the paddle shifters on the steering wheel, but it will hold that gear for just a few seconds unless you have the selector in 'S' (Sport).
The powertrain proved reasonably good on gas; we averaged 20 mpg in about 80 miles of driving, split about equally between low-speed city driving, highway cruising, and foot-to-the-floor performance testing. But pricier premium fuel is strongly recommended.
Steering feel is way better than you'd probably expect in a crossover vehicle—even one with a performance edge. The RDX's steering wheel feels very naturally weighted, actually gives some feedback of the road surfaces, and returns to center without ever feeling artificial. On-center feel is quite light, without that artificial heft you find in some newer vehicles, yet it doesn't require frequent adjustments. And the RDX's SH-AWD system expertly sends more power to the wheels that can use it the most. On a soggy day, around a smooth ramp, we felt this dance a little more intimately. There, the RDX's front end plowed first, sending more power to the back wheels, then it felt as if the stability system and all-wheel drive reached a harmony of sorts, compromising at a very slight state of understeer. It's all-weather confidence inspiring, and more fun than you'd expect in a crossover.
Supposedly, braking-system components have been updated for 2010; although this reviewer can't reach into the archives accurately enough to remember what they were like in the previous RDX, they feel perfectly boosted with a nice, firm pedal.
The 2010 RDX feels quite firmly damped but moderately sprung, so while it turns in with relative crispness, it's designed to keep it safe yet satisfying for any sane driver's needs on a curvy road while also absorbing major heaves quite well. The downside is that the RDX's ride is busy; it's not jarring, but it gets thrown around by pitchy surfaces. Positively, there's little or no road noise and wind noise.