Not intending to stop the poll, but here are interim results.
Looking at how many are 6.3.3 or below vs. 6.5 or above,
the results are evenly split for individual users, with 19 in each group.
If you add-in two of our resident hi-tech gurus, they are both maintaining their clients at 6.3.3, so depending on how you count their results, either slightly more are still with 6.3.3 or below OR a significant majority have not upgraded.
Among those speaking out in this thread, no one is describing major issues with the more recent versions.