You hit the nail on the head with the phrase "particular installation". There's certainly a fun factor to a bass horn, but if you have to live with it in a domestic space the size / performance trade-off is a no-win for the horn.The thing that Bill Fitz always harps on in his articles is "look at the output in the passband". That's all well and good in a club but the horns he builds are almost always best for kick drum on up - that 60-70 Hz region. For music reproduction you need good response at 40 Hz and that just makes it impractical listening at 10 or 12 feet away. Edgar has his fancy horn designs but he always has to have a sub for realistic reproduction. ALE horns go all the way down, but with a mouth at 5 feet X 5 feet they're pretty hard to accomodate in a ranch house.
Every design I end up admiring looks like the 4Pi - which looks like Lansing's original Iconic - which looks like the JBL K-series speakers - which looks like every Westlake plus a heavy doese of steroids. For audio in a domestic environment it's simply the best way to go.