What an interesting and useful review -- thank you! Encouraged by this assessment, I just ordered a set of these speakers from B&H ($150, including shipping). They should be here tomorrow, and I'm hoping for the best.
A bit of back story:
I took delivery of the new (late 2012) 27" iMac a couple of days ago, and was incredibly disappointed by the speakers. Zero base, tinny treble, and lackluster mid-range. How some reviewers described them as amazing is quite beyond me.
It didn't help that the 2010 iMac it replaced had a very decent sound system. I felt like I was going backwards, at least in the audio department. I knew I would never get used to the total lack of performance, which is what started me on a search for alternatives.
So I may post a review of my own, either here or on the B&H site. I'm keeping expectations moderated, and will be happy with any significant improvement over the status quo.