Paradigm 3f, KEF reference 3, Monitor Audio PL300II

I wouldn’t pay $15,000 for any of those without at least auditioning Legacy Audio Focus SE at around $10,000. Focus SE is a more full range speaker than any of those, rated down to 18Hz bass extension, and you get the AMT ribbon tweeter/mid driver. For me, the problem with the Paradigm Persona 3F is that it is a pretty small and bass limited speaker to be paying that much for. It is only rated down to 48Hz. You have to go up to the Persona 7F to get a speaker of the scale of the Focus SE.  Heck, you could get a set of Legacy Aeris for just a bit more than your $15K price. The Monitor Audio Platinum II line has been getting rave reviews, and you can’t beat being able to audition speakers in you own home before buying.

When considering speakers, or anything desired or needed, one just about has to look at what is there in pre – owned. For the same money.

Its nearly well, at least myopic not to do so.

We’re all facing this question from time to time. If possible, take a little road trip and get at least some inkling of the other missing link. Spending this amount just about dictates it. Again, if possible.

IMHO the single issue of contention is warranty, if all else is on a level playing field with what ever seller.

Therefore the question becomes, is my $$$$$ better spent on higher performance or a particular esthetic and assurances, which BTW may well end up forcing me to ship the new speaker off if needs be, just as it could ocurr with the used one?

I’ll say this and close. I’ve had speakers that ranged from 25 yaers old. 30 years old. Several new ones. And some from 2 to 5 years of age. The most ancient of them did eventually require me to get them refurbished and luckly two sets of them could be done by the orig maker. I still have them. The newer ones are all gone. I don’t miss but one pr of the dozen or more I’ve owned. Only the refurbished ones remain along with a couple sets of monitors and all sound just great. Only one pr were of ‘flagship’ quality.

Higher priced speakers usually include more robust builds, especially those one can capture for near double the investment of say $10K to $15K, or $25 – 30K.

It adds to the conundrum, but it’s a nice mystery.

Good luck.

In your price range, I would try to give a listen to the Sonus Faber Olympica 3's... They are a truly fantastic speaker for the money.  

Loudspeakers are a personal choice. So it's best not to rely on others experience. This is what I learned in the past 2 years looking for loudspeakers. Nevertheless, I have listened to all the loudspeakers you mention in the past several months.
All the loudspeakers that are on your list - I could live with them without any issues. The KEFs and Monitors are accurate loudspeaker and can be as neutral as a PSB Imagine T3 with the right ancillaries. I highly encourage to find out a dealer and listen to the Paradigm Persona 3F/5F. They are amazing loudspeakers. I demoed them in a "not a good setup" and they really sounded good. So, if a right room, they will have the chance to shine. I found the Sonus Faber to be a bit too warm for my preference.
If you get a chance, try to locate a Spendor dealer and listen to a D9; I think you will like them, even though they are priced below your budget.
What are your room dimensions and the equipment you would use to drive the new loudspeakers? What is your current setup?