I own a pair of ESL57 refurbished by Wayne Picquet of Quads Unlimited, and could not be happier.
They sound amazing within their limitations. It's true the sweet spot is small, but oh so wonderful. For vocals they can't be beat. There is also no reason to have to "babysit" them. They are quite robust, and with Wayne's rebuild you don't have to worry about overloading them. The bass response is also much better than most realize.
While they are fairly large, they are also so transparent that they do have a tendency to "disappear"......