I'm starting to wonder if Lambda-series Stax models are underrated, if for the sole reason that nine times out of ten, if someone even mentions Stax here outside of the big Stax thread, it's about the SR-007 or SR-009, the really expensive flagship models.
Even in Head-Fi's latest buyer's guide, you won't see anything electrostatic until you hit the summit-fi section. Unsurprisingly, there's the SR-009, but there's a big opening in the $600-1,000 price range that could easily accommodate a 'stat setup, amp included.
It may just be electrostatics in general being under-the-radar, but even the Koss ESP/950 is getting more recognition now, from the looks of it. (I've got to try one of those some day. Reviews are mixed coming from Lambda fans, but overall, they hold their own very well.)
I suppose the real question is "Why does no one consider the electrostatic models that aren't the flagships?" There are some great values to be had buying used ones, especially if you already have a speaker power amp of some sort to power the sets that come with transformer boxes.