My choice would be Infinity's Servo Static One. I owned a pair in the past after having a single pair of KLH Nines. The SS-1 was a great speaker - electrostatic mids and highs along with a super 18" woofer that went down to 20Hzs. Problem was, it was unreliable, service was poor, and it was built out of "bubble gum and tape." The KLH Nines were great, but you really needed two pairs (Double Nines), to realize their full potential. They needed a large room to sound best. My suspicion is the Sound Labs are the best electrostatics around. I heard them once and wanted to own a pair but could not afford them...yet.
Best Electrostatic loudspeaker?
Many of us have found that nothing make the magic happen like a pair of Electrostatics. It's been an evolutionary road for me, starting with various dynamic systems, then ribbon/dynamic hybrids, then full range planar magnetics (Maggies), then Electrostatics. So those of you with experience in Electrostatics, which do you think is (are) the best designed and executed example(s) of the breed?