I also picked up a few and burned them in for about 50 hours before installing. I used a .1uF in my speaker crossover as a bypass to the in series caps, a 1.0uF as my phono stage coupling cap, and a .01uF as a bypass to a V-Cap OIMP in my preamp output coupling cap.
After the 50 hour burn in and installation things sounded very well balanced, but flat. Another 10 hours made them open up, where I got the top end extension back. Another 10 hours and later Sunday night I heard the dimensionality return. They now sound very nice indeed. Well balanced, extended, airy and without any hint of hardness or sibilence.
I bet there is a bit more burn in to go, but they are sounding very sweet indeed right now.