I have played Crossovers from my start. After trying the slider and listening to a chromatic I think I will stick with the diatonic. It is tougher on some notes but when I listen to the really good players all seem to have a diatonic in their hand. I feel its what music you like and what sounds best to you. I have yet to see the best players topped by a chromatic and the notes I get from a good crossover seem to beat any of the slides I have. They get little play, primarily because of the note quality. Cost factor is lower and when some maintenance is needed the diatonic beats em all hands down.
I have heard Buddy Greene live and Charlie McCoy recorded, both had diatonic harps and sounded about as good as one can get. just my 1 cent worth,