The most efficient models are where the largest differences lie. The Opel has a two versions of the new 2.0L common-rail diesel with 127hp or 150hp. The Vue instead will offer two completely different hybrid powertrains. The less expensive mild hybrid system carries over the GM belt-alternator-starter system from the previous Vue (read the ABG Review) mated to the 2.4L engine. The second hybrid that will show up next year is the two-mode system that we already saw recently in the full-size Tahoe/Yukon mated to the 3.6L V-6. Further out in 2009 we should see a plug-in hybrid variant of the two-mode system. For comparison, the diesel Antara is rated at 26.4mpg/34.6mpg city/hwy while the mild hybrid Vue gets 27/32 mpg. The hybrid numbers are for 2007 model, '08 numbers aren't out yet. We'll have to wait a while yet to get data on the two mode.
What we won't see is a diesel, at least not yet. At some point as the fuel economy regulations get tighter we may end up seeing a diesel/hybrid combination, although by that time we might also see something like the E-Flex powertrain from the Volt in a cross-over platform. For now though the performance is comparable but if diesel engines start to catch on in the US market anything is possible.
[Source: Wards Auto World]