Is the Shuttle derived system a good deal?

Rand Simberg at Terresterial Musings doesn't think so.  As for me, I've been pleased with re-using this system for the now.  That could change though, since my education on this subject continues.  By the way, the link isn't about the Shuttle system per se, he just has a short blurb on the post which shows his opinion of the Shuttle derived system now being pursued as policy- to wit:

If NASA is smart, they’ll use both Falcon and EELVs for crew transport, so they have redundancy. What the Air Force really needs is a NASA to not develop a new Shuttle-derived vehicle, which it doesn’t need, and doesn’t have the budget for, but Congress is insisting that it build anyway, for no reason other than job preservation in Alabama, Utah, Mississippi and Florida.

Yes, the government is a big money waster, no doubt about it.  But I like the idea of using the big external tank for other things besides just ditching it into the ocean after it has finished thrusting a payload into space.  With the continuation of the shuttle based system, this may be at least a theoretical possibility.  Not that something similiar can't be done in another way, though.