Pros:
The Medium Silver G is the only Spirocore string I've tried (I've been playing on Jargar and sometimes Larsen strings for many years, and used Dominants as a child), and I was surprised by the great projection and very bright, complex, zingy sound.
Cons:
The string has a much smaller playable area than other strings: in the area around the bottom of the fingerboard, where I would play passages marked 'sul tasto' but also just anything where I want a soft, quiet sound, the string doesn't respond properly, but produces all sorts of strange growls and squeaks (like a very bad wolf note, but on the open string). It's also much more sensitive to variations in bow speed and pressure than any other string I've played on. I actually thought there might be a fault with the string, so I sent a video to Thomastik-Infeld and they assured me it was all quite normal for a Spirocore Silver! For me this sensitivity/instability makes it impossible to combine the string with Jargar or Larsen A & D as I had planned - the playable area of the string is so much smaller, and the right hand technique required is totally different. This is a very unforgiving string and I would have to significantly adjust my technique to make it work. I tried it on two very different cellos and had the same issues with both.
Other:
Thomastik told me that both the Chrome and Tungsten Spirocore strings are much more stable and have a much larger playable area, so they can be successfully combined with other steel strings. They said the Silver has a "very wide sound beam" and a "very rich but not very focused sound," but is unstable and can also be more likely to highlight any problems with the instrument. Also, in case anyone else has read online that Yo-Yo Ma uses Silver Spirocores combined with Jargar, apparently that's not true and it's much more likely he's using Tungsten Spirocore G & C with the Jargar upper strings (the silver actually looks different, while tungsten and chrome look very similar).
