What is the purpose of the question? A purchase decision?
The reason I ask, is that if you were to look at the numbers, there\'s still probably more Akai out there than anything else...but that \"popularity\" has limited relevance to a software sampler user.
Giga is probably the most widely developed format of the last three years.
You can get from Akai or Giga to most platforms, so those two are probably the most convertible. That said, compatibility between sampler platforms is about to go the way of the dodo as their feature sets begin to drift away from each other. The blessing and curse of progress...