The biggest "problem" is the controller does not use seconds to time with. So it's next to impossible to extrapolate figures from another type of head and not really easy to calculate the times. Also dodging and burning gets a bit wierd. Then the filtration is not in any filter values resembling what you are used to seeing on a subtractive unit. You just have times from 0 to 255 for each color then there's a setting for raising or lowering the general exposure. It has a probe but I never really figured out how to use it to read a negative and calculate exposure and contrast. I found my PM2L did fine reading it on focus mode. Another gripe is when the focus tube starts to go bad, it will shut off much quicker than it should and make setting up a print a hassle.