Only complaints seem to relate to the fact that the service is almost too easy to use -- you wont even notice when you've already shopped audio tracks worth of tens of dollars. Apple also reported that it has sold over 20,000 iPod portable audio players over the last weekend in the U.S. and has received over 110,000 orders for the player.
It seriously looks like Apple has finally figured out something that record labels just couldn't understand -- offer a legal, relatively cheap way to purchase (virtually) unrestricted digital audio tracks from a massive audio catalog and you have a winner.
It is rumoured that Apple has plans to launch a Windows version of the service later this year, but company hasn't confirmed the rumours yet. Company has announced that it will extend the audio catalog to include 500,000 songs by end of the year. The audio tracks sold are encoded by using AAC format, which is one of the standardized audio formats within the MPEG-4 standard.
Source: News.com