I managed to track down a set in Vancouver, and I have had them on for a few days now. I am happy to report that the pitch has stabilized already, pretty much.
My first impression was surprise at how dark and gut-like they really are. I don't mean they sound just like gut, but that they have some of the qualities of gut that I really like, and in surprising amounts; particularly the beautiful attack. However, they have much more sustain than a gut, and a more focused sound and pitch, which I like. The ringing notes have some of that appealing funk that you get with gut. I have played mostly on Olive and sometimes Eudoxa, but only on the D & G. In the past, I have experimented with various strings on the bottom, and once tried an Olive E & A, for about half an hour (anybody wanna buy em???), before I realized that I just couldn't go down that road. Waaaay too thumpy and cloudy, and with not enough sustain for me. I would have to qualify that by saying that if I played only arco, they would probably have been my string of choice.
Regarding the Evah Pirazzis, I was concerned that the bottom strings might be too gut-like also, and thus too dead sounding for jazz (like the Olive E & A, for instance), but they seem to ring very nicely. Overall, the strings seem quite responsive (ie: more dynamic range) and louder than the Obligatos, which I have been using for a few years. They also sound absolutely beautiful with the bow, all the way up. In fact, these are the first strings I have ever played that make the E string sound full rich and even clear up in the thumb position. They offer, however, a big change in tonal balance, which may take some getting used to for someone coming from a brighter string. I wouldn't say the E-Ps are a replacement for gut (if you really want that sound, you need the real thing), but they are a very nice sounding string, overall. They give every indication of being stable in pitch, which is very important to me, and why I just can't use gut anymore. I guess I am too old and cranky for all that fussing.
I reserve final judgement, however, until I have gigged and recorded with them a bit.
I should mention that I am playing them on a 1963-ish Pöllmann Gamba.
KL