I gave it an abridged spin at the Virgin yesterday, at one of their cd scanner hubs[a great thing, btw. you can play almost every US-released cd to get a taste before buying].
I know, it's sometimes impossible to deduct a real value of an album from 5 minutes at the listening station, but Sustain didn't grab me.
reading these posts, especially the mention of similarity between Sustain and Miles electric work makes me curious to check it out again.