I shot Trannie for years and I must say the quality is about as good as it gets it is also easier to scan and there is less grain, There is a trend to shoot neg for its muted colour range and wider latitude particularly in the fine art market and some find e6 a bit shouty so it could be said that the choice of film is as much about subject as output. I would suggest that so long as your metering is accurate there is a great deal of satisfaction to be had from shooting trannies. On the cost front e6 is a lot less than neg and you do not need a contact to see what you have.