KEW - I'm using Harbeths now. I had a pair of Ohm MicroWalsh Talls for a few years, which was my first departure from true time coherent types. I never saw a step response on the Ohms, but from what I gather, they were pretty darn close to time coherent - very simple 1st order crossover, which handed off to the tweeter at 8k. Essentially a full range driver (8k down to ~ 40k) and super tweeter. They shared a lot of the qualities of time coherent speakers, but without some of the drawbacks (listening position...).
The Harbeths are the complete opposite of a 1st Order xover type of speaker. Very complex xover - but I love the sound - incredible speakers -and they're the perfect apartment speaker. I've never heard a monitor sound so good at low volumes (good for the neighbors).
As far as audio concepts go, I really like Harbeth's approach. Alan Shaw, the designer, doesn't recommend fancy cables or expensive amplifiers, and explains that Harbeths sound great right out of the box - no break-in necessary.
On a professional level, we still use time coherent speakers where I work. One room has a pair of Lipinski monitors, which are one of the best studio monitors I've ever heard.