GameTrailers has an interesting mini documentary series about the soundtracks for all three games if anyone is interested.
Mass Effect 2
Mass Effect 3
Sadly, there's no interview with Clint Mansell and no discussion at all about what went on there, and Jack Wall is still saying that it was his decision not to return for ME3. I'm sceptical, but given how proud he clearly was of the Suicide Mission track maybe he really did choose to go out on a high note.