If you are travelling alone you would want the armrest by the aisle as this gives you more privacy. Every window seat alternates between a large armrest by the window or by the aisle. Finally, the A330-300 has a 1-2-1 layout with forward facing seats.
This means a 1-2-1 layout with direct aisle access for every seat. The new seats on the B787-900 are the typical reverse herringbone seats found on many airlines such as Qatar.
The B787-800 and A330-200 seats are similar to Qatar’s B777 seats. Hainan have 3 types of long-haul business class seats, all of which are fully flat. Last year we saw business class fares under £1000 to Shanghai from Prague. Hainan Airlines are based in China and have a 5* Skytrax rating. They don’t yet fly direct from London, only Manchester but the better deals are often from outside the UK. Hainan Airlines Hainan airlines new A330 business class seats