I agree. We just got our first Prius; the new 2008 Base model. Love everything about the car so far... Except rear view. We have difficulty seeing what's going on back there when backing up. I guess we'll have to learn to make better use of the side mirrors.
I've read this knock concerning the "blind spot" of the Prius. Someone wrote that he wouldn't buy one because of this safety issue. I'd just bought mine, so I assumed it was true; until the next time I was out on the interstate, changing lanes and such. I've got to argue that this is a totally undeserved criticism. I've driven cars that have a real blind spot; my wife's '98 Eclipse for example. The upswept body contour left no possiblility of seeing what is to the drivers right and to the rear. By contrast, in the Prius, I've found that when using the rear view mirror, you can see a great view to the back right through the upper and especially the lower part of the rear glass. With the lower part of the glass, it gives you a look at space closer to the car, than if you were looking "uphill" through a typical back glass. Coulped with the side mirror view, I don't believe much can hide back there. I would say it's one of the best rear/right side views of any vehicle I've ever seen. I just did an experiment using a cardboard box. I sat it in my "blind spot", but could see it just fine in my passenger side mirror.
I agree that the view out the rear windows is adequate while driving. You can see the car behind you just fine. We haven't driven it on the highway yet. I'm glad to hear that you don't experience any blind spots. Also ,I'm more comfortable using the side mirrors when going forward. Like I said, we just got the car a couple of days ago. We're still getting used to it. But when backing up I'm accustomed to twisting around and looking out the rear window. When I do that, I don't feel that I can see what's going on by the taillights. I need to turn back around to check the side mirrors.