I'll Chip In again with the owned Quad ESL 57's bought in the Late 90's as a 1 Year Old Quad Full Serviced Speaker.
These and another pair are a refurbished Stacked Quad Array.
These are easy to surpass and difficult to surpass.
I really have a good gauge on the Stacked and Single Tier Strengths and Weaknesses.
I use other Speakers for Periods of time and can forget about the Quads, and as a result certainly have the Quads Shortcomings laid out bare to witness.
Plug the Quads in to the Mains and connect to the System, and immediately the beating oneself up begins for not having them in use.
I would suggest in the UK at the prices these Speakers can command, they are the HiFi Bargain of all Bargains. As an influencer in the modern world, this Speaker has much to reveal that will win many admirers.