Best speakers under $500? Fire away!

you not only can't tell by the numbers, the published numbers are not always accurate or measured the same way...

Have you considered focal 705?  8ohms / 89db 

I can give a personal example the McIntosh integrated amp MA6700 has a power output of 200W ,my McIntosh MC152 power amp has only 150W theoretically my power amp should be less powerful than the MA6700 but it’s not !
I heard them both my amp is much powerful,transparent and detailed than the MA6700 ,That’s show you the published numbers are not always accurate or measured the same way...

https://www.audiogon.com/listings/full-range-thiel-audio-cs3-5-floor-standing-speakers-2017-03-09-sp...
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 Under $ 500 MA Bronze 2 is one of the best of the best with sensitivity 90 db / impedance 8ohm making it very efficient and easy to drive, speaker of the year on What Hi Fi .

http://www.whathifi.com/monitor-audio/bronze-2/review