Armour seems to be working just fine for most folks. After it was reformulated back in 2008/2009, users had problems but it seems to have been reformulated again (especially the lower dosages, under 1 grain) and people who had trouble with the reformulated Armour are doing well on the current Armour.
As for Erfa?? Erfa changed their mfg facilities from Belgium to Spain and ever since, there have been complaints. The STTM website even shows how different the 'new' Erfa is to the 'old' Erfa. The 'new' is a shiny tab with spots and a deeper indentation of the letters/numbers on it.
I used to use the old Armour and changed to Erfa when Armour was reformulated and there were shortages. Erfa was... WAS.... just like the old Armour but the 'new' Erfa left me dizzy/light-headed and lethargic within just a few days. I have since changed to WP and life is good again.
Bottom line... if I had to choose between the two.. Armour or Erfa... if they were my only choices, I would choose Armour. But I would make sure to get the Armour in the smaller dose size, regardless of my daily dosage requirements. In other words, if my dosage is 2 grains of NDT, I would request that my prescription be written for 4 - 30 mg tabs per day or 2 - 1 grain tablets per day. We should be splitting up our dosage into smaller increments spread thru out the day anyway.