QR303 (DOH-HEL), QR302 (HEL-DOH) and QR848 (DOH-KUL)
I decided to lump the review of all 3 flights under one post as these flights offered similar experience using the same type of plane (and hence cabin).
Unlike the A330-200, the A330-300 experience was much better. Unlike the former, A330-300 seats are 180 degree full flat and newer with more storage space allocated. As A330-300 is longer, the Business Class Cabin thus has more seats (30 vs 24 in A330-200) and is not cut off by the galley. Seats are still configured in 2-2-2 making it less attractive than those on Dreamliner and A350-900 (or Qsuites).