Most anyone who has been a middle child knows how it must be for the 2010 Cadillac STS. Slotted between the headline-grabbing, Euro-flavored CTS and the perpetually popular, old-school land yacht DTS, the STS goes nearly unnoticed, garnering less than half the sales of its siblings. This large luxury sedan seems to have everything it needs to get attention -- crisply tailored sheet metal, strong performance, commendable handling that belies its substantial size and enough high-tech gadgets (such as a blind-zone alert system and adaptive cruise control) to keep early adopters deliriously happy.

Despite its in-the-shadows status, we've always liked the current Cadillac STS, feeling that its performance (the powerful V6 essentially makes the V8 version irrelevant), supple ride and composed handling deserve mention. The latter quality, in particular, is truly impressive, as the STS's athletic moves almost make you forget you're driving a 2-ton luxury sedan. A price tag that can be thousands lower than European rivals' doesn't hurt either, even if it's partly due to a few mediocre-grade interior plastics.

However, the competition in this segment -- already tough with the likes of the BMW 5 Series, Lexus GS and Mercedes E-Class -- is even more so this year with Hyundai's new Genesis flagship, which offers powerful V6 and V8 engines, a handsomely crafted cabin and a hard-to-resist bargain price tag. There is also Acura's all-wheel-drive RL to consider as well as the aforementioned CTS, which offers an even more sporting drive as well as a much lower price. Overall, the 2010 Cadillac STS is worth a look if you're shopping for a roomy midsize luxury sedan, but you'll definitely want to drive the competition before making a decision.

The 2010 Cadillac STS is a large luxury sedan available in five trim levels – three V6s and two V8s. The V6 comes in Luxury Sport, Luxury and Premium trims, while the V8 comes in Luxury and Performance trims.

The V6 Luxury Sport comes with 17-inch wheels, leather seating, aluminum interior trim, eight-way power front seats, dual-zone automatic climate control, remote keyless entry and ignition, satellite radio, an eight-speaker Bose sound system and OnStar. The V6 Luxury (yes, it's a step up from Luxury Sport) adds wood trim, front seat power lumbar supports, a CD changer, Bluetooth, driver memory settings, heated/ventilated front seats, heated rear seats, a heated steering wheel and rain-sensing wipers. The V6 Premium adds 18-inch wheels, upgraded braking, steering and cooling systems, limited-slip differential, automatic level control, rear spoiler, auto-dimming rearview mirror, headlight washers, auto-dimming xenon headlights, an upgraded surround-sound audio system and a navigation system.

The V8 Luxury is equipped similarly to the V6 Luxury minus the ventilated seats and plus the automatic level control. The V8 Performance is equipped similarly to the V6 Premium and adds an adaptive suspension, blind zone/lane departure alert, a sunroof, a head-up display and adaptive cruise control.

Many of the upper trim features are available on the lower trims via assorted packages. Furthermore, the two top trims (V6 Premium and V8 Performance) can also be optioned with the Platinum package or the Performance Handling package (though not both). The former features chrome wheels; a unique grille; upgraded leather seating; leather trim for the dash, doors and console; and Olive Ash wood accents. The latter adds upgraded Brembo brakes and high-performance summer tires.

The standard engine on the 2010 Cadillac STS is a 3.6-liter V6 that produces 302 horsepower and 272 pound-feet of torque. The optional engine choice is a 4.6-liter V8 making 320 hp and 315 lb-ft of torque. Both engines come only with a six-speed automatic transmission, and both can be ordered in rear-wheel-drive or all-wheel-drive guise.

In performance testing, the STS V8 reached 60 mph in 6.3 seconds. Cadillac estimates put the V6 at 6.5 seconds to the same speed. Fuel mileage estimates range from 17 mpg city/26 mpg highway and 20 mpg combined for the V6 to 15/24/18 mpg for the V8.

Antilock disc brakes (with brake assist), stability control and a full complement of airbags are standard on every Cadillac STS. The airbags include front-seat side and full-length side curtains. There are also a number of available advanced technologies designed to prevent accidents, including lane-departure warning, a blind-zone alert system and active steering. The latter is available only on AWD V8 models, and is notable for turning the front wheels into a skid when the rear wheels lose traction. Braking is strong, with progressive pedal action and an impressively short 120-foot stopping distance from 60 mph.

In government crash tests, the STS earned four stars (out of five) for both driver and passenger in frontal tests. In side-impact tests, the STS scored four stars for front passengers and five stars for rear passengers. The Insurance Institute for Highway Safety awarded the STS a rating of "Good" in frontal-offset crash tests, the highest score possible. It scored a second-best rating of "Acceptable" for side-impact protection.

Although large in size, the 2010 Cadillac STS sedan feels three-fourths its size when driven with enthusiasm -- yet it rides like a supple luxury car when you're gobbling up miles on the highway. Cadillac offers an optional Magnetic Ride Control suspension that includes Touring and Sport modes. In Touring mode, the Cadillac STS provides a cushy ride and composed handling, although the car will still dive into the turns with unwavering composure and never feels as if it's sprung too softly. In the Performance setting, the handling is a little sharper and the ride a bit stiffer, but the STS handles so well in Touring that we question the necessity for the two settings. The torquey V6 is more than ample, with acceleration that matches the V8's. Considering the higher fuel economy, the base-model STS would be our pick over the pricier V8 version.

Depending on trim level, the STS's cabin is fitted with aluminum accents and perhaps real wood trim as well. Fit and finish is solid, and luxury buyers should be pleased with this Cadillac's generally high-class ambience. Minor demerits include the use of some low-grade plastic trim pieces that put the STS at a disadvantage against the admittedly more costly European and Japanese luxury sedans. The overall design is also on the dull side compared to the classy confines of the STS's sibling, the CTS.

Controls are straightforward and easy to use, with the exception of the confounding memory-setting procedure for the driver seat, mirrors, radio and climate controls. Unlike with traditional systems, which place buttons on the door or driver seat, you must dive deep into the navigation touchscreen to set memory functions. It's frustrating and unnecessarily complicated, but at least it's something done only occasionally. The trunk is also a bit small, with 13.8 cubic feet of total capacity.