I owned a pair of 570 and then 580 for a couple of years. Mated to tube and ss amps, they were better than any entry level speakers I had owned. I went to the 580 for more bass but found the 570 was a tad smoother, more refined between the two. I liked these more than some audiophile darlings like Vandy 2CE sigs mainly for classical which accounts for 80% of my listening. The strings were more refined through the JBL horns, the Vandys were rough in that regard and that little midrange driver got very congested on orchestral peaks. Same issue with Revel F12. Bettered the Usher cp 6381 as well.
My current Kef R700 are better in all aspects than the 580, they should be given the price difference.