I never liked SoundLabs and would venture to say your ETs would sound better. I would someday like to have Sanders ESLs and see if I can find a way to modify them to use a direct drive amp. To me they are a great "personal" speaker because of the narrow sweet spot.
Few know how maximize dispersion in a panel. The curved panel is a method, although I once read that Roger Sanders may have been onto the curved panel first, but decided against producing them. Jim Strickland was on to something special before Acoustat blew up, and Roger Modjeski kind of stumbled onto the same track and developed a few tricks to get wider dispersion from a flat panel.