I was putting together a Den system about a year ago and auditioned both speakers. I bought the KLH 5’s. They sound more open and natural for the music I listen to (1970’s to Current Progressive Rock, Classic Rock, Heavy Metal) and remind me of how music sounded as a teenager. I really like the passive attenuation control that adjusts the mid and high frequency output. I don’t think you would go wrong with either speaker, but the KLH 5’s just sounded better when playing Gabriel era Genesis, Yes, King Crimson, Dire Straits, Bowie, Led Zep, etc.
I currently run them with an Audio Research SP17 preamp and McIntosh 225 amp. The turntable is a Rega P3 with a new ND5 cartridge, the streamer is a Bluesound Node, and the CD Transport is a Cambridge CXC with a DacMagic 100. Great little system.