Size/Market Segment: Hybrid vehicles range in size from compact economy sedans to nine-passenger full-size SUVs. The largest population of hybrids resides in the midsize sedan segment.

Price: As a rule of thumb, hybrid vehicles are about 20 percent more expensive than their all-gas counterparts. The cheapest hybrids are in the low-$20,000s while the most expensive luxury model costs well over $100,000. New hybrids are being planned by almost every manufacturer, so waiting a year or two will probably drive down the price while increasing the options in terms of manufacturer and vehicle type.

Engine/Fuel Economy: Hybrids break up into two categories: fuel-efficient hybrids (getting from 35-50 mpg) and more performance-oriented hybrids (getting from 20-30 mpg). The latter category still offers relatively good fuel economy, but the emphasis is on performance. That performance might come in the form of outright speed, as with the hybrid luxury sedans from Lexus, or in the form of pure functionality, as with the Chevrolet Tahoe Hybrid, which is designed to be as rugged and off-road-capable as a regular Tahoe.

Safety: In general, hybrid vehicles are as safe as all-gasoline cars, but concerns have been raised about accidents that damage or expose the batteries for fear that electric shocks are possible. However, hybrids have been on the market for eight years now and accidents of this kind have not been reported. Additionally, manufacturers say they have taken steps to educate emergency responders so they can help accident victims without risking injury.

Luxury Features/Convenience: Most hybrids are slightly more upscale than their corresponding gasoline counterparts. This is due to an effort by manufacturers to justify the premium that buyers pay for the privilege of saving gas. Upper-level luxury models feature the latest in electronic gadgetry and amenities.

Passenger Capacity/Interior Space: Early hybrid vehicles were limited in interior space because the batteries took up room behind the backseat or in the cargo area. Newer models have gotten better at maximizing interior space, so this is no longer an issue for hybrid buyers. Toyota's Highlander Hybrid, for instance, can seat up to seven passengers, while the hybrid Tahoe and GMC Yukon can accommodate up to nine.

Cargo Space: Some hybrids are not as flexible in their use of cargo space because the rear seats do not fold down, while batteries tend to eat up trunk space. Likewise, hybrid SUVs usually lack anything in the way of under-floor storage because the battery pack is located here, and payload capacity (the amount of weight you can safely carry inside or on top of the vehicle) may be slightly reduced. In most cases, though, hybrid vehicles are nearly as practical in this regard as normal cars and SUVs.

Operating Costs: Some drivers of early hybrids reported accelerated tire wear because of the narrower tires that offered less rolling resistance for improved mileage. But tire wear on today's hybrid vehicles should be approximately the same as that of a similarly sized vehicle with a conventional drivetrain. Other operating costs, such as oil changes and routine maintenance, are comparable to normal cars. In some cases, brakes last longer due to hybrids' regenerative braking systems. Manufacturers offer longer warranty coverage for the hybrid-specific components, usually eight years, so you're covered if something goes wrong with the batteries or electric motor. One of the few unknowns is the cost of replacing the hybrid batteries, though manufacturers contend the batteries are designed to last for the life of the vehicle.