I am a Klipschorns fan so my opinion is a little bias,if I had the chance to get a deal on a pair 60th anniversary,my reason would be they rarely cone on market used and if you decide to sell them you can.I am sure the jubilee's are a great speaker and provides life like sound ,I want my speakers to sound good and look good too and to me the 60th anniversary Klipschorns do both.
If your main criteria is what will sound the best, as you say, there is but one choice.
I'd your question is whether it is worth the extra 20 percent to go for Jubes, in my opinion they are worth more than the typical 3 or 4x what a pair of good used Khorns would run. Couple that with being able add an 1802 later on you can use it for anything. HT, 2 channel, whatever.
What is it going to primarily be used form. HT, 2 ch?
You won't need to worry about diminishing returns until you get to the point of upgrading drivers, center and sub options.
If you have other criteria maybe looks/WAF, space concerns (which doesn't appear to be a problem) or something else I can't help you with that, it is just too subjective.
I have VRDs for 402s and McIntosh solid state on LF with active crossover.
I think you are operating under the mistaken assumption that a separate active crossover somehow changes the sound of your amp, adds coloration, etc. A good active crossover won't do that.