Mac version is quite a bit bigger than the Windows one, and I've got it on the list to add that as a FAQ on the site explaining why. On my connection, it takes about two minutes to download the Mac version (195mb) vs. two seconds for the Windows one (460kb).
Reason for the size difference is because I used WineBottler to convert much of the existing program to Mac. Converting to Mac includes some additional resources for everything to work correctly, which is what adds to the file size. Didn't know about WineBottler until I started looking into things, but it's pretty nifty and might be useful for someone looking to do something similar:
WineBottler |*Run Windows-based Programs on a Mac.