Bosch make a similar claim on their website and product packaging too. In neither case does it appear to be true. My test car was my Honda Element, which in theory makes a good test rig because its windscreen isn't very curved at all. Both the driver- and passenger-side blade are 20-inch items. The blades were easy enough to install, using the almost universal j-clip type mount and they certainly look the part once installed. But when you wipe, you get a very strange effect.
On the driver's side, the blade makes contact all the way across the wipe area up to about 60°. After that, the outer 25mm or so won't contact the screen any more meaning you get a narrower wipe the further over it goes. It's immediately noticable if you put these blades on directly from an older set without cleaning your windscreen as you can see the difference in wiper area very clearly. In addition to the weird decreasing-wipe, you get a smear that is pulled back down the windscreen on the back stroke. This is the problem on the driver's side. Mouseover the image to highlight the area the Rain-X blade misses in red and to show the backstroke smear:
The car Bibles product reviews: Rain-X Latitude and Bosch Icon wiper blades.
Product Reviews
Rain-X Latitude and Bosch Icon wiper blades
Tested May 2008 
Website: www.rainx.com and www.boschautoparts.com
Rain-X and Bosch are both marketing bracketless wiper blades now. The idea is that they look good when replacing OEM items on a lot of new cars, they wipe well because there are no pressure points created by a traditional 'spider' frame, and they're ice-resistant because there are no pivots or springs to ice up. Finally, both the Rain-X and Bosch blades come pre-curved on the principle that no windscreen is flat, and they have aerofoils to keep them pressed against the screen.
That's the theory anyway. In practice it's a little different. I tried the Rain-X and Bosch items and they both suffer the same problem - the one thing they claim to eliminate. Neither manufacturer's blade is actually able to keep itself pressed against the windscreen across the whole length of the blade. This means that you get an uneven wipe. The following bullet point graphic is from Rain-X's website:
On the passenger's side, the opposite is true. The blade makes contact all the way across the wipe area once it's above about 35° but below that you lose a good 50mm of sweep as it gets down to the park position. Careful examination of the blade reveals that when parked, the outer 75mm doesn't even touch the windscreen. This first photo shows the problem on the passenger's side. Mouseover the image to highlight the area the Rain-X blade misses in red and to show the backstroke smear.
The second one shows how much of the blade doesn't touch the screen when parked. You can see the rain in the area it's passed over:
I'd like to say it was a problem with my car so we tried both the Rain-X and the Bosch blades on a Toyota Camry, a Dodge truck, a Toyota Yaris and Subaru Impreza. The problem manifests itself on all these vehicle types. We tried them at speed to see if the aerofoil would help to press the blade against the screen but it made no difference. Plus, if you search for reviews using Google, you'll find spotty comments here and there complaining about the same thing. The quality of the wipe in the centre of the blade is good - there's no streaking to speak of, and if you use the blades on a nearly-dry windscreen, there's no chatter or skipping. But the problems with the variable contact at the ends of the blades are too much of a problem especially given that's one of the big claims both manufacturers make. They're distracting in-use because of the smear on the backstroke too. I'm sure the bracketless idea will work well in the snow - I've had the traditional spider-type brackets ice up on me a lot every winter, but is that enough to compensate for wiper blades that simply don't do the job they're supposed to? I suppose it depends how picky you are. If you can live with little annoyances, then these blades are actually pretty good. If you find that little annoyances bug you, then best not buy a set of these.
December 2008 update
Now the snowy season has arrived, I've had a chance to test these blades in snow and ice, and it turns out that this is where they really shine. I've upgraded the review to 4.5 stars because of this. With no frame, there's nothing for the snow and ice to freeze into place. This means the blades are able to conform to the shape of the windscreen even in sub-zero temperatures. Combined with Rain-X Anti-Ice in the washer tank, I can use these blades to clear solid ice off my windscreen now, and when the blades are submerged in snow after a day's parking outside, they easily clear the snow off the windscreen at the first wipe.