I asked the tech guy why I did not see many people have probs with the 77mm maf but I did see some have probs with the 75mm maf. He told me the electronics on 77mm maf were better than the 75mm maf.
He also told me the better buy was the 80mm maf cause the electronics were the same as the 77mm maf and since the 80mm maf was made of plastic it could be bought for less money.
Many on this board have the ProM 75mm maf and say they have had no probs at all.