SONY Plextor multiple recorders

Hi everybody! I would like advice on buying a pair of recorders ... Sony DRU-840th or Plextor PX-820sa? Even if the first is ide and the second is concerned ... I serve to burn simultaneously then would buy two equal. I removed fit for my purpose? Thanks!
PS: I can not find that model of sony even on the part of the world. Rid of mice suggest some source?

Why those two models in particular?

Explained better what I will try and give you a hand.
For speech to burn the same thing you mean?