You don't have to stream the digital copy or commentary version from iTunes. You can download them to your computer.
I just finished the enhanced commentary, and enjoyed it immensely. It featured the director, producers/writer, editors, composer, visual effects supervisors all talking over separate sequences. It paused frequently and rewound to illustrate a point. It featured picture-in-picture. It included drawing lines on the screen to emphasize sequences.
Yes, it requires an iTunes account, but I am one of the many people who have that already.
Thumbs up from me.