I haven't used the 800 but that doesn't mean I have no opinions
First, I absolutely hate touchscreens on the bike. I find them generally unusable.
On the 800 specifically, it was the sole reason Aaron Gulley was forced to DNF the AZTR this year. He was a clear contender for the W so that was extra painful I'm sure. The 800 erased his track from memory and could not be revived.
You know the 2 years of firmware updates that eventually got the 705 working reliably? The 800 is still early in that process.