I own the KEF reference 107. It is a stellar speaker regardless of age.
Some things to confirm and consider about this model before buying:
Make sure it has a working Kube equalizer. Especially at the $2000 asking price. If not, you can knock off $500...then start looking for a kube.
Ask if the quad internal 10" woofers have been refoamed recently. If you can't get an honest answer, plan on this needing to be done shortly after purchase.
The T33 tweeters are ferrofluid cooled. The ferro fluid is easily cleaned and replaced, but does take a minimal amount of speaker disassembly and skill to replenish. Ferro fluid is available at parts-express and there is an active 107 owners forum on AK.
The kube requires you either have front end seperates or an integrated with pre-out/amp in connections.
Yeah, they need a bit of care to own, but they are still a reference level speaker set in my opinion. They're easy to place, and offer tunable bass quality I've not yet experienced in any other speaker in this price bracket.
That said, the Goldenear Triton 1, and Tekton Double Impact appear to offer some of the most bang for the buck in a modern speaker. If the maintenance, care and feeding of an older system turns you off, it seems one of these two offerings could serve you well. They will certainly be a bit more plug-n-play.