Here's some more info from Funimation from their YouTube page:
Plus, I already mentioned this in the free streaming thread, but it makes me mad since the rental listings are integrated with the free listings (which itself is sloppier IMO than Hulu's or FuniVideo). And, it's not just these two anime companies doing it, since YouTube launched this in time for Sundance and are offering some movies from the festival for a limited time; heck, I was thinking about posting this on TEB instead of the anime board due to this. I won't be using it since I don't want to use Google Checkout, but I can see YouTube Rental's purpose.
As for the rates, they do reflect the usage of said rentals and varies from content provider to content provider. Funi's 99-cents-an-episode fee is good to see the video for 24 hours, while TAN's $1.99-an-episode and $3.99-per-movie allows you to see these videos as many times as you want for 7 full days. Most of the Sundance movies are good for multiple viewings for 48 hours. For movies, they're in line with what is offered on other services (ie Amazon VOD, iTunes, PSN, and Xbox Live/Zune) if not better on certain usage cases.
As for Xam'd, it's a special case and should not be compared to this. Especially considering that the $2.99/$3.99-per-episode (SD/HD) fee is for a subtitled-only anime that, for a short period, was available ONLY IN AMERICA and can only be accessed/rented/viewed on a PS3 and/or a PSP. Quality of the series aside (thought it was good, but playing devil's advocate), that bolded sentence is something you don't get every single day.