Initial Quality – In the J.D. Power and Associates 2009 Initial Quality Study (IQS), which measures owner satisfaction with vehicle quality after 90 days of ownership, the Lexus IS received 5 out of 5 Power Circle Ratings when compared to other vehicles in its class, and was the top-ranked entry premium vehicle in the study.

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Performance and Design – In the J.D. Power and Associates 2009 Automotive Performance, Execution, and Layout Study (APEAL), which measures owner satisfaction with performance and design attributes of a vehicle, the Lexus IS received 3 out of 5 Power Circle Ratings when compared to other vehicles in its class.

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Vehicle Dependability – In the J.D. Power and Associates 2009 Vehicle Dependability Study (VDS), which measures owner satisfaction with a vehicle’s reliability after three years of ownership, the Lexus IS received 3 out of 5 Power Circle Ratings when compared to other vehicles in its class.

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Fuel Economy – The 2010 Lexus IS 250C is equipped with a 2.5-liter V-6 engine driving the rear wheels through a six-speed manual or six-speed automatic transmission. The 2010 Lexus IS 350C has a 3.5-liter V-6 engine powering the rear wheels through the automatic transmission. According to the EPA, the IS 250C is rated to return 18 mpg in the city and 26 mpg on the highway with the manual, and 21 mpg city/29 mpg highway with the automatic. The IS 350C is expected to get 18 mpg in the city and 25 mpg on the highway.

Our review vehicle, the IS 350C, averaged 20.2 mpg during a week of mixed driving with a highway emphasis. Combined with the car’s 17.2-gallon fuel tank, this actual fuel economy figure results in an approximate 345-mile range between fill-ups of premium unleaded.

Safety – The National Highway and Traffic Safety Administration (NHTSA) had not yet performed crash tests on the 2010 Lexus IS convertible at the time this review was published. Because of the significant structural modifications made to create the convertible, the NHTSA does not carry the sedan’s ratings over to the convertible.

According to the Insurance Institute for Highway Safety (IIHS), the 2010 Lexus IS receives a “Good” rating in the frontal offset crash test, a “Good” rating in the side-impact crash test, and an “Acceptable” rating for rear impact protection. Evidently, the institute does not distinguish between the sedan and convertible, except to state that its findings apply only to the IS 250 and IS 350.

Environment – According to the EPA, the 2010 Lexus IS 250C consumes 16.3 barrels of petroleum annually with a manual transmission and 14.3 barrels of petroleum annually with an automatic transmission, resulting in carbon footprint ratings of 8.7 and 7.7 tons per year, respectively. The 2010 Lexus IS 350C consumes 17.1 barrels of petroleum annually, resulting in a carbon footprint rating of 9.2 tons per year. Air pollution scores were not available at the time this review was published.

Note: This review was published on December 29, 2009. It may not reflect data that has become available for this vehicle since that date.