Business Class on the B777-300ER usually consists of Rows 6 and 7, then a galley and toilets, then Rows 8 to 11.
I prefer being in the mini cabin and in there I prefer Row 7 as the screens are on the bulkhead wall if in Row 6. If you like a window then Row 7 is not the best choice as the window is misaligned and awkward to look through, but if you prefer an aisle seat then Row 7 it is.
Seats are fully flat but not horizontal.