Popular Science has a negative review of the iTunes movie rental service. It's complete crap. The review, that is.
Jon Chase used a relatively old laptop with outdated software to review a new service. That's like road-testing a brand new Ferrari on an old, rutted dirt road; any conclusions you might draw from the experience are sort of meaningless. Jon's review also misses the larger point of the service. Rentals are primarily a strategy to help Apple capture the living room, not the home office.
I've tried several online movie rental services, including Amazon Unbox and the XBox Marketplace. I've been using the AppleTV and ITunes movie rental service for a while now, and it is the most seamless and consumer-friendly of the bunch, by a wide margin. Set-up took about 5 minutes. I've now rented about 10 movies from iTunes, with only one (minor and easily fixable) technical problem. That's not to say iTunes is flawless; there are a few quirks and the content is still pretty thin. And the usage rules that Jon complains about are real and stupid. But they aren't Apple's fault; they are required by the movie studios.
While it's still early days, I'd say we're a lot closer to electronic movie distribution becoming mainstream than Jon's highly slanted review would suggest. I, for one, won't be visiting a video store any time soon.