While it certainly wouldn't have drawn such an impressively high bid had it been painted by a less renowned artist, there is a sense of style and movement and radiantly surreal life there that is distinctly Van Gogh. The color palette while vivid is also complex and well considered and the composition holds surprises as well, being more sophisticated upon further examination than initially meets the eye. While it's part of a series, this being
Still Live Vase With Fifteen Sunflowers 3, I can still see $77 million for this, being somewhat iconic as it is, far more easily than I can see ten million pounds for the Gauguin that is the topic of the thread.
The only reason I can see that the Gauguin is expected to fetch such a price is the history contained within the imagery. The sunflowers are dead because the famous painter of them is dead also, and this was intended to commemorate his passing.