Up until now, I've never read in landscape mode on any of my ereaders. It just is not practical. I don't think it was possible anyway on any of my Kobos outside of using KOReader.
With the Forma, CoG is lower when reading in landscape mode and the balance is really nice as well. I have both buttons set to go "next". Reading in landscape mode is very nice on the Forma. Something I never thought I would do.