I am a big fan of the Storm 2 Ultra used on my MT09 Tracer and the Storm 3D XM currently on my BMW R1200RS. I rode the latter yesterday in the Cotswolds on cold, damp, slimey roads and they were excellent. The Tracer was transformed compared to riding with the OE Dunlops.
If the ST are better than the predecessors then they will be superb. The Tracer has gone, replaced by a Triumph Explorer and this will be fitted with the Storm 3 or ST Spirit, depending on what is available when the OE Metzelers need changing.
As a bonus, the Avons always seem to be cheaper at Chris Mullins in Gloucester compared to PR4 or Metzeler 01.