I have no issues with sweat and the Alpha pads. Although I did with the stock e-protein leather pads. I would say though that the time of year matters very much for me too. In the summer my ears get sweaty with the Alpha pads when the relative humidity is up over 60% and the temperature outside is in the 80s to 90s (I live without air conditioning too). So far this winter I have never sweat wearing the TH-X00 with Alpha pads.
I'm sold. Where did you get your Alpha pads?