Yeah The Stirlings and Amphion both look great too!
I adore my Spendor Classic 3/1 for most music in my 4x4m room. Generally they are superb across all genres, and have so much more gratifying scale, texture and impact compared to the small sealed 4/5 Spendors I had before.
But, on that small spread of music (think electronica, modern pop or EDM with its overblown bass in the recording), I actually prefer a more bass light speaker, with its ease of placement, lack of room interaction and tight presentation. Not having to have them way out into the room.
It's so music dependant though, as lots of older funk and soul / Jazz, or I die (e.g. Chic, Labi Siffre, Duke Ellington etc), even Arctic Monkeys or Kasabian sounds way better with the larger 3/1. Just a fun, rhythmic bass underpinning the music. It's a shame music, particularly depending on the age of recording, varies so much in how balanced the bass sounds.
With say 70% of the music I listen to, my current 3/1 are more gratifying to listen to.
So while I don't think the P3esr, Stirling or equvilent will be my main speaker, it could be fun to swap it in, for those bass heavy tracks. Or, late night background listening when they're back up against the wall (it's in main bedroom).