Ya they look like a well built baler, and with the cutting system it would make nice feed, also like the way they have them big augers is the corner , that is like Deere which I believe is a better setup. But like you we have 604SM  not sure if I would want to drop back to a 5 ft baler, we like making are silage bale's around 62" to 64", but are dealer is going to bring the 504pro out to try , so will let you know how it goes.