Venkat,
Following Vincent's reply, here is one more piece of statistics
http://danse.cacr.caltech.edu/polls/results.php?sid=22
Of course, the number of people using Rietveld software is more than 269 (number of answers in the survey) and even more than 771 (number of subscribers of this list) but still the results have some representativity.
It seems that user friendliness matters, but only if one doesn't have to pay for it.
Cheers,
Max
