Click to embiggen.
The new books emphasise landforms and geography, unlike the previous covers which featured military and medieval iconography.
They're striking, but to my mind don't quite capture the feel of the series. In particular, A Clash of Kings featuring (presumably) the Red Waste on the cover is a little odd given that only one chapter takes place there. It's also mildly disappointing that Voyager still haven't recombined A Storm of Swords and A Dance with Dragons into a single paperback volume each, given how many larger or comparable novels out there are available in one paperback volume (The Wise Man's Fear, The Naked God, Atlas Shrugged, The Lord of the Rings, Diana Gabaldon's novels etc). I'm also hoping that the Game of Thrones tie-in note are stickers and not part of the cover, as they are rather incongruous. The current paperback set rather subtly and elegantly notes the GoT reference in a small section on the back cover, which is a better idea.
The new covers will be available alongside the previous ones and will not replace them outright.