Fred Miranda gave us a fine list on p. 8, #18: Which lens is better? Voigtlander 21/1.4 or Loxia 21/2.8?
I think a key issue missing from the list is that the Loxia 21mm is well weather sealed, and the Voigtlander 21mm Nokton is not at all weather sealed. Sometimes that is a big factor in favor of the Loxia.
I don't have any difficulty mounting or dismounting Loxias, but I have ordered two Lens-Grips from PocketPano for possible more safety.
Fred Miranda gave us a fine list on p. 8, #18: Which lens is better? Voigtlander 21/1.4 or Loxia 21/2.8?
I think a key issue missing from the list is that the Loxia 21mm is well weather sealed, and the Voigtlander 21mm Nokton is not at all weather sealed. Sometimes that is a big factor in favor of the Loxia.
I don't have any difficulty mounting or dismounting Loxias.