After a lot of waffling, I finally decided to take the plunge and try out Amazon's Unbox, as well as Netflix's Watch Instantly service. Overall, I'm fairly pleased.
The bad: The waffling came about because of system requirements. Netflix requires Windows Media Player 11, with all its DRM "improvements," which had me leery. I don't really trust Microsoft to have my best interests at heart as regards management of my digital media, so I didn't really want to install their upgrade. However, on reflection, I realized I don't use WMP that much, anyway, so I figured it wouldn't be an issue. The biggest problem I have with Netflix, though, is that it requires use of Internet Explorer as a browser in order to watch their offered video. I'm a dedicated Firefox user, and IE frankly gives me hives. But if it's just for that service, I can deal.
It was my understanding that Unbox requires use of the latest WMP version, as well, though I don't see it on the system requirements list at Amazon. In any case, it at least doesn't force me to use IE, since their player is independent of the browser. While Netflix runs streaming video, Unbox works with downloads, which are limited to use on 2 computers. Neither system is Mac compatible (boo).
The good: Netflix has a very good selection of movies and TV shows available for viewing--over 5,000 according to the website. If you're a member, you can use one hour of viewing time per dollar you pay for your monthly membership. So if you have one of their basic subscriptions, you're looking at 5-10 hours of viewing/month. If you're a spazz like me and have a grandfathered (from *ahem* years ago) super duper membership, you're allowed, well, a lot of viewing time. I'll never use it all up, but at least it adds a bit more value to my membership, since I have a bad habit of leaving movies laying on top of the DVD player for months before I get around to watching them.
Anyway, I first set the system up on my son's computer so the kids could watch the Sonic the Hedgehog animated series. They finished that up and then apparently couldn't find the time to look through for other shows they might enjoy, so I went ahead and set up the system on my own computer and started watching The Office from Season One. The software was easy enough to install once I'd gotten my Windows updates finished, and runs pretty smoothly. Netflix seems to feel my DSL connection is on the low end, speedwise, so it delivers the lower quality versions of the available movies, but it's not bad--definitely on a par with the free streaming service offered by the network websites.
Also at Netflix, they're offering new episodes of Heroes the day after network broadcast, I guess to make up for NBC's pulling the show from iTunes. They also offered the premiere of Californication before it was broadcast on Showtime, and Dexter's Season Two premiere for a limited time.
At Amazon Unbox, you can download episodes of a good number of TV series for $1.99 and episode--the same price as at iTunes. NBC's shows will continue to be available here even after they pull everything from iTunes at the end of this year--I guess NBC was happier with the DRM at Amazon than they were at iTunes. They also have movie "rentals" for $3.99 each. These have to be viewed within 30 days or they will explode. Actually, they automatically delete themselves. Once you start playing them, you have 24 hours to finish watching, so if you have to leave on an emergency trip to Zimbabwe in the middle of your movie and you won't be back for a month, you're out of luck. If you have a TiVo, you can watch downloads on your TV. You can also hook the TV into the computer to watch, or watch downloaded video on a select number of portable devices (iPod not included--another boo). Portable video files come with your download.
My experience with Unbox so far has been limited to free content. I "purchased" (can you call it purchasing when it's free?) three supplemental videos for Bones ("Couples Counseling" videos--short and fun little asides to the story as it's playing out on the series). At first I had some difficulty using the software--it wouldn't download my videos. I had a suspicion I'd entered the wrong password, but couldn't find an option in the software to correct the issue. After an uninstall and reinstall, I was able to enter the right password and download the videos. All that went swimmingly, so I suppose my difficulties could be attributed to user error. It was a bit frustrating, though, to not be able to figure out how to fix my password without uninstalling.
In any case, both these options seem to be very viable for catching up with shows online. If you want DVD quality viewing, you're not going to get it here, but if you can't wait for the DVD releases, both Unbox and View Instantly can help you keep up with your viewing, or check out samples of shows you might not watch otherwise due to scheduling conflicts.