I have not experienced the AM 787 inflight but have been onboard. You can read more
here.
On the 787-8 the downside of most seats is that the foot cubby is really restrictive, depending on your length. The first row and the mini cabin have more space for your feet in the full flat mode.
I may have a look in the 787-9 next week but will not be flying. Anything particular you'd like to know?