Many of you have probably read our Diesel and Hybrid SUV Comparison (Diesel and Hybrid SUV Comparison: 2009 BMW X5 xDrive 35d vs 2010 Lexus RX 450h vs 2009 Mercedes-Benz ML320 BlueTEC vs 2009 Volkswagen Touareg TDI) wondering where the GM representative is. After deciding on a 4WD/AWD diesel versus hybrid comparison test, we then had to make sure the SUVs we included would be similarly equipped. Therefore, the Tahoe, Yukon, and Escalade hybrids were eliminated as contenders because they all come standard with a third row. That alone could've made this an unfair comparison. But despite that, some of you still may wonder how one of these vehicles would've lined up against the BMW (which charges $1700 for the optional third row), Mercedes-Benz, Volkswagen, and Lexus. Here's a general overview.

The base prices for the vehicles in this comparison vary from an estimated $42,000 for the RX 450h to $51,200 for the X5. The 4WD Tahoe Hybrid starts at $54,210 ($54,680 for the Yukon) and the AWD Escalade hybrid is $76,635 before adding accessories. The Tahoe Hybrid's price is about $12,000 over a base 4WD and $9000 more than an LT2 trim level; Hybrid content falls between the LT2 and LTZ grades. An Escalade Hybrid is roughly $11,000 more than an Escalade AWD, and the Platinum trim package adds another $11,750.

The GM hybrids all use the same powertrain: a 6.0-liter gasoline V-8 and dual electric motor units sandwiched in the four-speed automatic transmission, rated at 332 horsepower and 367 pound-feet total output. This betters the comparison-test fleet's horsepower by at least 67, but it's the second-worst torque. (Those with more torque are diesels. What else would you expect?) While they have some weight-saving features to limit the hybrid penalty to roughly 350 pounds--similar to adding 4WD to a rear-drive SUV--they still have 5850-6050 pounds (empty) to haul around.

The GMs' wheelbase, at 116.0 inches, is longer than the longest wheelbase tested here, the 115.5-inch X5. Track is widest front and rear, and its 202.0-inch length is significantly longer than anything else here. The next-longest vehicle, the X5, is 11 inches shorter. The GMs have the most front-row headroom and overall shoulder room, yet interior dimensions are midpack otherwise. It stomps the rest in cargo volume, though--108.9 cubic feet of storage behind the front row as opposed to 75.2 for the X5, 72.4 for the ML, and 71.0 for the Touareg.

On the road, the big GM hybrid 'utes feel much like the standard versions when friends are on board. The brake pedal is touchier, and sidling into a tight garage or parking spot might not be as smooth as you're used to. Golf buddies and lanky families of four or five will be more comfortable in the hybrid GMs than their conventional counterparts. The hybrids use unique front seats for weight savings and they seem as comfortable as the regular seats, but they aren't as thick so there's a significant increase in second-row knee space. The GM hybrids all use a bench-seat second row because of the battery pack beneath it, and as the widest SUVs around, they do well at three-across seating on that middle bench. The Tahoe/Yukon/Escalade use a three-person bench with two headrests and a 50/50 split to remove them for a flat cargo floor.

When we tested a 2WD GMC Yukon Hybrid, it did the 0-to-60 sprint in 8.3 seconds and the quarter mile in 16.2 at 88 mph. A nearly identical-weight 4WD Tahoe LT non-hybrid posted 8.3 seconds to 60 and 16.1 at 86 mph in the quarter mile; these and the 45-65 times are all in the same spectrum as the ML and Touareg diesels.

We have no directly com- parative fuel economy data. However, on 70-mile loops that included Interstate, urban, and winding roads all between 100 and 1500 feet above sea level, a Tahoe Hybrid delivered 19.8 mpg, right on its 20 city/20 highway mpg rating; a Yukon 5.3 brought 17.7 (14/20).

In the two-mode hybrids, when you mash the pedal from a stop, as you might to cross a highway, there's a momentary delay before the gas engine is lit and full thrust comes on, and while the reasons are different, the effect is very similar to the from-rest turbo lag in some diesels. The Escalade Hybrid's mileage is likely to be slightly lower than that of the Tahoe and Yukon, maybe 1.0 mpg, because it doesn't have the same aero tweaks, adds 100-200 pounds, and in most instances will be optioned with 22-inch wheels.

Despite the torque from electric drive, the GM hybrids are limited to 12,000 pounds gross combined, so maximum tow rating is 6200 pounds (2WD Tahoe/Yukon). That's better than that of the RX (3500) and X5 (6000), but falls short of the ML's (7200) and Touareg's (7716). For towing on open highways, we'd probably recommend a standard 5.3-liter Tahoe/Yukon, rated at 8400/8200 (RWD/4WD).

The Tahoe and Yukon Hybrids come as 2WD or 4WD vehicles; the Hybrid is the only Escalade with low-range gearing--though apart from scaling a slimy launch ramp, we can't imagine anyone will ever use it. Ground clearance matches that of non-hybrid models' and the Hybrids' cleaner side steps might last longer in the rough stuff, but the bits modified for aero and weight benefits--deeper front air dam, 18-inch wheels, and higher-pressure, low-rolling-resistance tires--all work against off-highway performance. GM does not list fording depth for any of these utilities, hybrid or otherwise.

Would it have been unfair to include the Tahoe or Yukon in this comparison story? Probably, considering that they're much larger vehicles than those tested here and come standard with three rows of seats. However, when you think about the capability you get for a comparable price, putting the GM SUVs in this context does make for some interesting conversations.