Wien I did the conversion, I had 4-5 days of ground school to cover the tech. differences and operational differences. After that I had 3 sessions in the sim, and then some supervision on line before release.
I have no idea about the potential costs for an employer, but it is regarded as only a differences training, so I would think this could be arranged in-house so to say. The cost would be far less than a full DHC8-rating, so I guess you could have a slight edge. But who knows these days.
I operate both versions randomly, and I must say they are two different beasts. Engine management/operation, landing technique and EFIS layout, being the major differences apart from the c***py climb performance of the -300 compared to the -400
