I have somewhat mixed feelings. I prefer PDF versions of most of my books because it's so much more convenient for me, and landscape fits nicely on a computer screen or a tablet, but really, it doesn't much matter, monitor is big enough for 2 page spreads, which are nice, so tips it a bit toward portrait so I can see both pages of a unit at once, and on tablet I can rotate it. At the same time the transition from landscape for the TRO and portrait for the RS in the XTROs is kind of a pain, so those, at least, would benefit from being portrait only.