I have both these days and although i'm currently using max a fair bit more than maya i'd say Maya. The main reason for this is the workflow. Maya's interface lets you work awful lot quicker than max does, because in max you constantly have to go looking through mass's of modifiers and buttons. The second thing a hate about max and this is only one little fault and there might be a way to help this, is the texture detail in the viewports is terrible and this is a big problem when trying to work from detailed image plains.