Since Krug was brought back it is Krug or Piper.
Based on my recent experience it is Krug about 20% of the time and Piper the remainder.
Not that I consider this a major issue, by the way.
However, one observation - and I think this is pur coincidence - but on several First flights recently the cabin has been full with over 50% being upgrades (before anyone asks how I now this, just trust me I do), these have been the flights with Piper. On flights where the cabin is not full, we have had Krug.
Again, I am positive this is just coincidence, but Sim is beggining to believe his taste for Krug is being penalised by upgrades. One to watch maybe....