I don't know from personal experience, but I've read on multiple boards about Aisen having a bad rep. Is anyone here familiar with Aisen?
Considering how many transmissions they make I am sure they have had some bad models however considering they are the largest transmission manufacturer in the world chances are most of their transmissions are just fine. Aisin AW supplies transmissions to 55 automotive manufacturers around the world, virtually every major OEM. These include General Motors, Ford, Mitsubishi, Nissan, Porsche, Saab, Audi, VW, Volvo, Hyundai among others.
http://en.wikipedia.org/wiki/List_of_Aisin_transmissions